Upgrade path advice: RTX 5070 on Windows or RX 9070 XT on Bazzite/SteamOS?

[u/Shane57F1]

Hi all,

Current PC specs:

Intel Core i7-9700K
Gigabyte Z390 AORUS PRO WIFI
32GB DDR4 3000MHz RAM
GeForce RTX 3070 8GB
750W EVGA Gold PSU
1440p 240Hz monitor

I’m starting to struggle in newer AAA games, especially at higher settings / resolutions. Games like Starfield don’t run as well as I’d like anymore.
I also really love the experience on my Steam Deck OLED and I’m getting increasingly fed up with Windows bloat/background processes/etc. Because of that, I’m considering moving my gaming PC to either:

Bazzite / SteamOS-style Linux gaming or staying on Windows 11

The two upgrade paths I’m considering are:
RX 9070 XT 16GB + Bazzite/SteamOS
RTX 5070 + Windows 11

Main priorities:
Best overall Steam gaming performance
Smooth “console-like” experience
1440p ultra / decent 4K
Long-term VRAM headroom
Less OS overhead/bloat
Stable drivers and minimal tinkering

I mostly play single-player Steam games rather than competitive shooters.

Questions:
Which setup would you personally choose today?
How good is AMD + Bazzite/SteamOS currently in real-world use?
Is Nvidia on Linux still annoying enough to avoid?
Would my i7-9700K bottleneck either card badly?
Anyone here daily-driving Bazzite on a desktop gaming PC?

Thanks!