Materialious is usable on Web, Android (TV too) & Desktop.
It can be used with Invidious or using its own YouTube backend.
Has its own account system with end-to-end encryption for subscriptions.
My problem with all of these frontends is that how do I discover new channels? Much as the Youtube algorithm is privacy invading, it also leads me to discover channels that I wouldn't have been able to otherwise. How do people handle this with frontends?