I’m planning to get the cheapest used t480 i could find in Beirut and upgrade the screen, ram, trackpad, storage, and battery and I was just wondering if you have any tips to share.
Current specs: CPU: Intel Core i5 8th Gen 8GB DDR4 RAM 256GB SSD NVMe 14" FHD"
My use cases besides simple Web browsing is programming (Python, C, C++ currently, but I do tend to learn a new language atleast once a year), light gaming (minecraft, indie games, and maybe some first person shooters), I plan to get tinto 3d printing and CAD to expand my projects into physical devices instead of just software, servers, and light arduino/esp32 expirementing on a breadboard.
Upgradibility and Repairability is something I care about. I’m gonna he putting Linux on it ofc and might expirement with changing bios in the future though still unsure as that will limit me to no egpu capabilities.
Anything else I need to know? Parts to upgrade, different models that would suit my use cases better etc?

The T480 (at least with the nvidia graphics) is not suited for light gaming. In theory you should be able to play games up to Doom 2016. In practice the thermal throttling is so awful that the GPU is throttled very quickly that you can’t even play Quake 3.
CPU and GPU sit on the same heatpipe so that you get to the throttling limit even if the GPU isn’t used that much.