Also sync is not that great for massive datasets: I tried to sync my 22k-ish Evernote notes to Apple Notes and it took days and I never got the same number of notes on all the different devices. If you are currently building your notes you will probably not encounter this issue, though.
I was considering obsidian, but the devs say that obsidian is designed for a maximum of 20k notes.
So, I'm already on the upper bound, as you are. Probably, obsidian would be slow if I import all my notes.
Evernote, on a Windows 10 Desktop, now works fast, at least for me. I think we undervalue this fact, we undervalue the fact that it is hard to make good note taking apps that can sync and search fast with more than 20k notes. I guess there are users with 60k notes!
They are currently still catching up to reach feature parity with the old native clients, but at least they are releasing more frequently --which means betting the house on Electron technology is paying off--.
I do not use Evernote any more (finally ended up with plain files in iCloud Drive and EagleFiler to top it off) but I am still following their releases as a paying customer.
I agree with you, though: Notes is really quite good. I'm not sure how Notes syncs, exactly, but for whatever reason it's not blocked by my employer.