Go into settings and add a ⚡️ emoji in the button configuration settings. Then restart the app. Your incoming zaps will still go to whatever your default receiving wallet is. You'll need an external wallet to send zaps, though, as Nostur does not have a built in wallet like Primal has.

It's been fantastic ever since I did that uninstall/reinstall. The only thing I notice still feels laggy is new notifications while I have the app open. For example, I'll receive a zap or happen to see a reply to one of my notes, but the notifications tabs won't update to reflect that.