I have a new F3 with 14 full build plate prints and a 100% success rate. Overall I have multiple printers and over 700 prints with an average of a 98% success rate. The F3 should be rebooted periodically because there is a memory leak in the current firmware.
I rarely clean the build platform. I pop off the parts, and feel the surface with my hand (in a glove) where the part was, and use a scraper to remove anything left behind. Usually there isn’t anything and I stick it right back in the printer.
I found long ago that wiping it down with paper towels and IPA often leaves lint and other residue that affects platform adherence. If I do wash the platform (with IPA), I also clean it with soap and water and wipe it down with a lint free cloth, then sweep it with my bare hand until I don’t feel any residue on the surface.
The bulk of learning how to get successful prints is learning how to orient and support parts correctly to minimize the peel forces. After a number of messy failures I have learned to review my prints one layer at a time in Preform before printing.
I rarely use the suggested orientation or support layout. Instead, I look at the slice and orientation for minimal support. If the slice has too much surface area, it will affect the peel forces. Orient the parts to make the layer slice as thin and small as possible. If you go vertical to do this, add more supports. The general rule is to orient parts so they build upon themselves.
Also don’t forget about Z-tuning. If the part is not adhering to a clean platform, drop the Z-height a little and try small test prints. If it is squashing the support bases (i.e., mini-rafts), raise the Z-height.
All in all, use a small test part that won’t make a mess if it fails and doesn’t use a lot of resin. If you suspect a printer problem, use the Formlabs test print first. If that comes out okay, the printer is fine. If not, open a support ticket.