Like others already advised you should be okay using an old laptop running Linux. Also get the paper server for minecraft as it is way more optimized than the vanilla servers
Edit: I almost forgot, using GraalVM instead of OpenJDK or whatever default Java installation is worth looking into. Doing that gave my Minecraft client a ~20% performance uplift
Also if you need help getting more FPS for a better (clientside) gaming experience feel free to reach out