Are those lines diagonal? Are they occuring at the entry/exit points on the layers where the head is moving to a new perimeter or layer? Sure, you can have an imperfect surface, but that ridge is a bit extreme. As Ed says, you have a bit much plastic coming out. Also, check the print preview careful...

The factory grease I got with my M2 looks like a white lithium grease to me. It does collect stuff, but since it is exposed, it is very easy to clean the lead screw by pressing a paper towel against it while you zero out the Z. Of course, no liquid oil should be used, as it can get down in to the mo...

Your tension looks fine, but Ed’s sprung screw looks like a great trick. I would probably look elsewhere for the cause. I have NEVER had to babysit a filament roll the way you described. I have accidentally had the free end of the filament get itself under another loop on the roll and have trouble f...

I printed mine in ePC, the filament I love to hate. Amazing stuff that has a 100% success rate in clogging my nozzle on the transition back to PLA.

Have you printed a fan duct to help focus the airflow at the nozzle? That may help.

You could also increase your infill thickness. Thicker infill stacks on itself better.

You could also increase your infill % so the bridging distance is shorter.

You may be getting some slight binding that is causing the motor to stall. Make sure to wipe down the screw so it is clean, then add a bit more of the grease (I think it is a lithium grease. There is a little cup of it included with the M2) down the screw. Just a little line of it is enough. Then ru...

Ed is correct, but you did not mention your retraction settings, so I just wanted to check and make sure you have some retraction enabled to relieve filament pressure and reduce stringing. Sometimes a slight vertical nozzle lift will help as well. If the stringing is VERY wispy and fine (smaller tha...

I recommend that you not use a Dremel. It is too aggressive, as you have seen . Just a small file or sandpaper does well to smooth things out. Also, you may want to get a small set of flush cutting pliers and an Xacto to use for removing supports. They do a cleaner job than a Dremel. Next would be t...

Nice of you to make those edits. You aren’t the first person to get a bit overheated when the printer first arrives and things aren’t going quite as planned. Many folks have to adjust their expectations a bit, as there is little in common with 2D printing. Your patience will hopefully be rewarded so...

I am not seeing the image in your second post for some reason. It sound like you are having some issue with the printed housing. It is possible that there is an issue with that print. Perhaps you need to remove the hardware and pass a small drill bit through the housing to clean up and align the hol...