Hi, good to hear it finally works, Thanks taking the time to try the game and give feedback !
On the perfomances, i just tried making a detailed world (not that much detail though), with the least triangle count and different textures/materials. Plus i used the new unity's URP (Universal render pipeline (i know you used unity in the past but i don't know if you saw the new updates)) which is really efficient for low end targets. Sadly i was thinking on upgrading to the HDRP (High definition render pipeline), but it's for higher end PCs or machines like PS/XBOX, etc..., but i'll try to make a URP version for my next games !