If you are looking into how to write game ai there's a few key terms that can help a ton. Look into anything related to the game FEAR there AI was considered revolutionary at the time and balanced difficulty without knowing too much.

A few other terms are GOAP for goal oriented action programming, behavior trees. And as weird as it sounds looking up logic used my mmorpg bots can have a ton of great logic as the ones not running a completely script path do interact with the game world based on changing factors.

Definitely look into keyboard replacement. I've replaced so many laptop keyboards and flipped the laptop or used it for myself from people too lazy to learn how to replace the keyboard. I have yet to run into a model that doesn't have one you can buy on eBay.

I would say anything but this one if you're looking for a printer as a tool. My mp select mini v2 has been wonderful for me but thats because I wanted to learn electronics and have 3d printing be my hobby. Not have it as a tool.

This printer has a mandatory bed rewiring that if not done can cause a fire or the printer to lock up. Has a odd z-axis screw that needs to be replaced as it has weird magic numbers to work with for nonstock firmware, and the board causes the motors to be incredibly loud. A bed plate that is recommended to have a glass plate added to it for adhesion and to prevent warping as it's only 1mm thick. And a very limited 120mm build volume.

I love this thing, it taught me soldering, it taught me about electronics and voltages, how to repair and tune a printer. The fact that the motors didn't make the printer loud but stepper drivers do. How fusion 360 and sketchup work. Plus the amazing part of gcode changes like arc overhangs.

I'm finally starting to be very happy with mine but its a ship of Theseus situation now.

I'm currently building a voron and utilizing my printer and my coworkers stock ender3. And tbh I love the ender3. Its great, and at your budget price range it'll do most things. $100 won't be great for anything safe to use resin wise. So before you make a jump for ender3 look up the differences between fdm and resin prints as ender3 is fdm.