This was mocked up on the phone but uses desktop modal, would need some tweaking for mobile replies, but similar concept.
Pressing new account button would generate a new npub every time and automatically switch you (hopefully).
Concept:
1. seamless npub switching on reply
2. Anon replies (throaway npubs)
nostr:npub1nje4ghpkjsxe5thcd4gdt3agl2usxyxv3xxyx39ul3xgytl5009q87l02j
Discussion
Switching btw different real keys is hard (impossible with browser extensions, possible with Nostr Connect or local nsecs), but switching to Anon is trivial, apps can just have a switch "Reply as anon" and sign this particular event with burner keys. zapthreads comment widget deployed on habla.news has that