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.
New pipe on the phone works pretty well. Better than YouTube ads. Although you can’t directly watch shorts without searching for them (as far as I know). I just watch those on Firefox with adblock.
Would recommend though.