I've had some issues with Invidious being unable to play specific videos once or twice, but the issues tend to go away after a couple of days.

I mean, we know Google and Youtube are both multi-billion-dollar corporations that are absolutely enraged by the idea that there could be any possible way for a commoner pleb like you to NOT have your online experience absolutely crammed with as many privacy violations and hyper-targeted ads as possible. Invidious having to constantly stay ahead of such powerful entities' attempts to block them out means that some errors and periods of downtime are perfectly excusable- what's important is continuing to support them in their fight.