I am making Roulette Wheel and I want it to have multiple different PBR textures, and those textures have their color,normal,roughness maps, for example: marble,oak wood,metal etc. It is for the games so if I do it by making UV seams on places I want some texture on and selecting those faces I want texture on I create new material, import downloaded textures,assign them to that faces and so on. But at the end it seems I have multiple textures ,and as I understand it, they should have all be on one texture and then move UV maps to match it as you like if you want it to be optimised. What is the right way for multiple PBR textures on one Game-Ready object? I hope question is clear, let me know if something is unclear.
You're probably talking about the trim sheet method where one material can be referenced by multiple parts of the same mesh. With the way you've UVW unwrapped that model, trim sheets wouldn't work too well. You'd need to straighten those circles into straight pieces. A trim sheet works by tiling but those pieces won't tile well at all. I highly suggest downloading a free add-on called TexTools which will straighten things like that out for you so you can then use them better with trim sheets.
I've created a short video demonstrating the best way to go about this, with your particular model.
Hope this helps! Using PBR textures with tileable textures.