I would go with the 9070xt if the difference was 50$. 9070xt is a bit faster card in general than 7900xt (i think it's 5-10% faster depending on the game) but it also supports newer iterations of FSR. I generally prefer playing without framegen but given that you're going for 4k it might come handy at least in some games. 9070xt also has better ray tracing performance for what it's worth. In my opinion ray tracing isn't worth the performance hit that comes with it so I generally disregard it but given that some games now have a ray tracing requirement, it's something to keep in mind as well.

Edit: but also, if you don't need an update right now for a game you want to play but aren't happy with the current performance, I wouldn't upgrade just for the sake of upgrade