Most modern games will be more than fine with 32GB of system memory.
Still not really enough information. We have narrowed it down to DDR4 and that you have a Zen 3 processor.
Motherboard can have either 2 or 4 slots.
Your CPU cooler could impact what type of memory you have room for.
Adding additional memory is generally frowned upon. For best results you replace all the memory with a new kit.
If you are after 32GB, it is typical to use 2x16GB DDR4 3600 CL 16 or 18.
Relatively cheap kit that will get the job done:
64GB of memory:
If price is no object you can pick up something like this for best possible performance:
Probably won't manage 4000 speeds, but it should run 3600 just fine.