arcade system

A raspberry is very affordable, but it may not meet all your needs (obviously the more you raise the price of the model the more you can have a smooth and enjoyable gaming experience).
My advice is to take a PC (the operating system is fine with the one you are most comfortable with, Linux or Windows to your liking) so as not to have it for exclusive gaming use but to use it perhaps for work purposes in future.
In case you choose a PC on the internet there are sites like PCPartPicker that have been made so that you can compare the different pieces based on performance and price, I highly recommend it.

(note that I am not saying that a raspberry is not good, but in my opinion it has different uses :] )