Seems like Piped and Invidious are both on their last legs. Public instances on both services are pretty iffy, they go down fairly often now. Freetube works well on desktop but no real way to sync subscriptions and watch history to a phone. Self-hosting Piped/Invidious might be the solution but I don’t know if it’s worth the upkeep when YouTube is actively fighting against it.
Self hoster of Invidious, I’ve just setup a docker instance with a Watchtower docker container running too for auto updates. No real maintenance needed.
NewPipe on Android
There are definitely times where things will stop working for a bit (due to Google shananagans) but the devs seem on top of it. So it doesn’t take too long before it’s working again.