nostr:nprofile1qqsth7fr42fyvpjl3rzqclvm7cwves8l8l8lqedgevhlfnamvgyg78spz4mhxue69uhhyetvv9ujuerpd46hxtnfduhszrnhwden5te0dehhxtnvdakz7qghwaehxw309aex2mrp0yhxummnw3ezucnpdejz7qnse3k is a better optiin for web apps on mobile than using PWAs.
Signing into PWAs using Amber generally requires NIP-46 signing, instead of NIP-55, which is used for native apps like Amethyst. I have always found NIP-46 signing to be inconsistent at best.
Keychat allows you to use NIP-55 with Amber to log into ANY web app, because keychat converts it to NIP-07, as though you are signing in using a browser extension. It's much more consistent.
NIP-46 can work, but it is highly dependent on the relay you are using for it, and I think there must be a very short timeout window where, if the client doesn't see the signed event in time on the relay, it just doesn't log you in.