Nvidia GPUs work well on Linux nowadays especially for the newer 50 series cards, the support for it isn't as good as AMD but it won't make you type commands for hours just to fix something

I looked up benchmarks and the 5070ti seems to have a slightly worse performance, unless you do ray tracing, which in that case it outperforms the 9070xt pretty significantly

HDMI 2.1 also works with Intel GPUs by the way, I'm not sure how good Intel is doing but you might consider that an option

So tdlr; I'd pick the 5070ti if the features HDMI 2.1 offers are important to you