I have a very similar use case so here is my opinion.

HARDWARE

-No dGPU unless this is your PRIMARY gaming computer. (Reason: better battery life, lighter laptop, with recent AMD iGPU you have decent performance for non-VR/not massive openworld AAA games.)

-recent AMD CPU. (Reason: better performance to watt ratio than Intel which makes a big difference for most of your use cases. Better multi-core performance which makes compiling code much faster. Massively better iGPU for light-medium duty gaming.)

-atleast 16GB ram if not expandable but as much as you can reasonably budget.

-16:10 or taller aspect ratio screen (16:9 sucks on laptop size devices, the extra height makes a big difference for school, coding, browsing, pretty much everything but watching 16:9 movies)

-Resolution: personal preference. IMO 1080p or 1920*1200 for 16:10 is ideal for 14" and below laptops. Lower resolution means better battery and on a small screen the PPI is high enough. If you are OK with a trade off of battery life and want a super crisp display then 2K is the highest I would go. 4K is retarded on laptop sized screens unless you are plugged in 90% of the time and you'll have to fuck with scaling then.

-metal body for stiffness and durability

-decent key travel (usually longer travel means better IME)

If you want to do machine learning/AI work professionally I use and recommend investing in a dedicated desktop with a large memory nvidia (cuda cores) GPU and installing the cuda drivers. Trying to cram commercially viable ai hardware into a laptop is a losing battle and you'll end up with a worse experience for both use cases, wont be able to fit large models in the memory anyways, and end up buying a desktop for AI while being stuck with a laptop that is worse for laptop use)

SOFTWARE

#1 Nobara OS KDE - best OOB experience for gaming IMO. Easy transition from windows. Has kernel fixes and many laptop specific fixes (asusctrl for example) by default which means you have a good chance of extra features like LEDs, fingerprint, etc working without tinkering). Fedora based.

#2 Linux Mint Debian Edition (LMDE6) - best non-gaming distro to learn and grow into IMO. Access to deb packages. Stable. (nobara has been stable for me as well, but it is LMDE's bread and butter). Ease of transition from windows. Can game just as well if you are capable of following simple instructions to configure the stuff done by default on nobara and pop (may need to manually change kernels, drivers, etc to get the best performance on new hardware)

#3 Pop_OS - used it for years, but I prefer Nobara after comparing. Ubuntu based so you have access deb packages without ubuntu's bullshit. Setup out of the box for gaming. I got fed up with failed updates, broken packages, and sluggishness so I swapped to nobara which has been a treat.

EDIT: you can snag some good deals on amazon warehouse deals (used-like new) laptops. These are usually just open box returns and if there is anything wrong you have 30 days to return it.

I recently upgraded to an Asus vivobook S 14x OLED (M5402R) for $780 CAD ($580USD) with a ryzen 7 6800H, 16GB DDR5, a 1TB gen 4 nvme, and it has zero signs of use, slight coil whine under load that I can only hear if I put my ear next to the keyboard and don't have any sound or music on (I suspect this was the reason for the return on mine since its a common complaint for this model. That's what I was hoping for since I'm not that picky and its worth the steep discount IMO.) Everything works oob on Nobara. I believe lenovo also regularly heavily discounts their previous gen thinkpads which are a great option, although the AMD configs are rare. Good luck!