I think you're being rate limited by your relays, when you change IPs it works for a bit
Discussion
Try using a VPN if it works, we know the issue.
So Dynamic IPs make Nostr act wonky?
No the opposite, many requests from the same IP would get you rate limited from relays.
That makes sense to be fair.
I use Amethyst over Tor at home.
When I’m out and about I use Damus, and Primal on my iPhone.
But I always cross-check clients to make sure.
But I also do use Nostr a lot 😅, so it could be that too.