That’s partly why I recommend an integrated N100, it’s a 6W, 4 core cpu:
https://liliputing.com/the-asus-prime-n100i-d-d4-is-a-compact-motherboard-that-measures-170-x-170mm-6-7-x-6-7-and-should-fit-in-any-pc-case-that-supports-itx-form-factor-boards-what-makes-is-a-170-x-170/
HDDs at 16TB goes for 5-6W in idle and around 10W when in use, but that’s the same whether it’s diy or not.
EasyRPG seems to be what I’m talking about albeit focusing on being compatible with an older RPG Maker and not only inspired by, Godot and those are a whole other ballpark and require a lot more coding knowledge to get into imo.