For me, from F-mount glass I'm keeping my 500PF, my 20mm f/1.8 (love this for landscapes), the 105mm micro (which can take a TC, unlike the z-mount version), and I just picked up a used 600mm f/4 for a good price.
Things I upgraded to Z-mount were the full f/2.8 zoom trinity.
I thought about getting the Z 105mm, but the inability to use a TC on it held me back. I may think more on it later, though. I'd love to get the Z 600mm TC someday, too... but it's out of my budget for the near term. I'll stick with the F-mount until that changes.
That's pretty much my standard Z9 kit now.
However, I'm keeping a lot of F-mount glass anyway. I still shoot film sometimes on an FM and a F100, I kept my D850, and I have some cool vintage glass that can be fun to use. None of it is going to be my regular working kit, but it has its purposes and I'll be keeping it. The only ones I'm on the fence about maybe getting rid of are a couple of my short D primes which I rarely find any use for now. But they're also not worth much for resale, so no harm in keeping them too.