PS4 Pro or PS5 for only PS4 games?

I have a large backlog of PS4 games that i want to play and am thinking of getting a spare PS4 Pro or a PS5.

There are just 1-2 ps5 games that i really want to play so there isnt any rush for me to get a PS5. Nor do i want to pay any upgrade fees for each game that i already own, so would prefer to just play them on a PS4 if that is the case.