The CR-6 SE is a GREAT printer, but it can bite you if you don't take a few precautionary steps.

I have a CR-6 SE. It does VERY high quality prints. However, I've run into several problems that were not design problems, but assembly problems. In some cases, it's cost me bad prints, trashed upgrades, and great frustration. Now, several months later, I've rectified most, if not all the issues, and now have a really great printer!

I learned these by trial and error, mostly error. If you'll follow these steps while setting up your printer, you'll have a much better experience with your prints..

BEFORE YOU TURN IT ON:

Take off the glass bed. Tighten EVERY screw in the aluminum bed below. Screws should be snug, but don't overtighten, or you'll strip out the holes.
STORY: I had put on a PEI bed on my printer, which requires a magnetic base attached to the metal base using adhesive. I was having severe levelling issues. I
had to tear off the magnetic base to tighten the screws. EVERY single screw on the bed was loose. I thought I could re-attach the base, but it was no use. I had to buy another. Performance improved.
Make sure the gantry is parallel to the bed. You can do that by manually lowering the head to the bed with a sheet of paper between the bed and nozzle of the hot end. It should rub evenly across the bed. If there's an issue, check your screws and make sure the gantry is secure.
There are four screws at the bottom of the printer. Tighten them up as well.
If the bed wobbles, adjust the eccentric nuts that are the shafts of the rollers. An eccentric nut is one in which the "central" hole is off-center. It allows adjustments of the rollers. There are many, many sites that will explain this in more detail.
STORY: Ever since I had the printer, I had a bed wobble. I tried to adjust the nuts, but still had wobble. Since it didn't seem to affect the prints at the time, I shrugged my shoulders and moved on. Recently I started having layer shift problems and squeaking (more on that later), so I tried to tighten a roller. I was working on a specific roller and trying to tighten it up. As I adjusted, I felt it "firm up." After that the wobble was gone! Perfectly dialed in - by accident.
On the Y-axis motor, tighten set nuts holding the gear to the shaft of the motor. Some threadlock might be a good idea.
STORY: On one of my prints, I started hearing a squeak. I thought it might be a roller, so I adjusted and lubricated them. It got worse and I started getting layer shifts. The canon showed here is supposed to have a straight barrel and carriage. After reading, it was mentioned that the set screws on that motor shaft might be loose, so I took a look. One was completely out and sitting on the floor of my enclosure, and the other was loose. I tightened one, but the other was cross-threaded. The bed could hardly move by hand. I re-set the cross-threaded screw and got it properly tightened, then re-tightened the first screw. With both properly tighten, the squeak was gone and the bed movement was silky-smooth.

YOUR FIRST PRINT PROJECT:

Print this project first: https://www.thingiverse.com/thing:4654645
The reason: the strain gauge that the printer uses for automatic bed levelling can sometimes be confused by strain on either the Bowden tube or the control cable. In my case, during automatic bed levelling, I was seeing the hot end stair-step up, higher and higher on each test point, thinking that the bed was two or three inches higher than it actually was. I thought I had a defective printer, until reading led me to this print. I installed the bracket and cover and never had a problem with the auto bed leveling again.

MAINTENANCE:

As with anything mechanical, maintenance is a must for smooth operation. Some suggested regular maintenance items:

Cleaning: occasionally vacuum out the inevitable scrap plastic that will collect in and around your printer. A simple vacuum hose should do the trick.
Lubrication: keep a can of dry lubricant or white lithium lubricant on hand. I use dry lubricant. There's a fine one by WD40 that you can pick up at any DIY store.
- Keep the Z-axis lead screws lubricated.
- Check, and OCCASIONALLY lubricate the Y-axis rollers if needed.
Cleaning the bed: I usually use 95% isopropyl alcohol, available at any drug store. Others will wash with a solution of Dawn soap - I haven't tried it, but experience in other areas suggests that this is a good solution. I've also used acetone OCCASIONALLY to renew my PEI bed. Since moving to my Fulament bed, I haven't had the need, so I don't know if I'll continue with the acetone.
Keep all fans clear of dust. It's worth checking at regular intervals, depending on your use.
Keep the belts adjusted. Not super-tight, just secure.
Filament: This isn't exactly printer maintenance, but it's maintenance nonetheless: almost all thermoplastics have an affinity for water: they absorb moisture. When they do that, they often become brittle - they snap easily. You can fix this with your oven, a dryer, a food dehydrator, or even your printer. There are lots of details out there for this. I use a food dehydrator.

SUGGESTED UPGRADES:

Firmware: My own printer is pretty basic; with my other printer, I've gone to open source Marlin, which has allowed different features and upgrades. I don't yet have a need on this printer. The biggest thing that would push me that direction is if I want to be able to change filaments mid-job.
The Creality WiFi box and camera are great additions which allow me to remotely monitor (or start, or stop) a job.
A good PEI bed (Fulament is what I have, and it's great) is overall much nicer than the glass bed (except with PETG or other higher-demand materials). Items adhere VERY well to the bed when the bed is at temperature. However, when the bed cools, those items easily release.
An enclosure: If you're printing PETG, ASA, ABS, or certain other materials, they can be VERY sensitive to drafts. I got the large Creality tent to enclose the printer. It's been a real help.
All-metal extruder: I've heard about CR-6 extruders cracking. I don't know if it's early models or not: mine has been fine. However, if I have problems with it, I'll definitely move to an all-metal extruder (I've already done it on my Ender 3 Pro).
All-metal hot end: I know it can be good, but if you're just starting out, or if you're only printing basic materials such as PLA, ABS, ASA, PETG or stuff like that, I'd probably not do that for right now. It's terrific once it's dialed in, but it can be a bit complex to get it working correctly.

I hope this helps you enjoy your printer and have terrific prints!

Before Your First Print