Roll20, Discord and OBS and some video chat app

So I was trying to do it with my MacBook Pro 2015 and it is not possible. Now I want to build a low to mid range pc just to do that. Can you advice my on what to get or build?

Why can't you do it with your Mac? Is it a matter of resources? Because you should be able to get OBS configured and then start the virtual camera, and pull that into either/or/both of Discord and Roll20. You can handle audio natively or, if you want a little more control, get VoiceMeeter and/or EarTrumpet (I use both -- it takes a minute to get it setup, but the control you get is worth it) . Granted... all of that is easier with an external monitor -- it's a lot to manage from a single screen. EDIT : Forgot EarTrumpet was a Windows10 thing. There might be a Mac analog.

I have two external monitors but with my 2015 Mac resources of cpu and memory don’t seem to be able to handle it

I did this for years on a 2012 iMac. There is an article in the wiki that might have some useful pointers.

Thanks guys, but I am hoping someone can indicate what are the actual memory, board cpu gpu requirements