I don’t rely on it at all because it likes to omit things I assume it thinks I won’t like. Plenty of times I’ll see a new video from a subscribed creator on the home tab to head over to subscriptions where I can’t find it but see previous ones.
If it worked that would be great, instead I use third party apps to manage it and would just stop using YouTube if those tools were unavailable.
PCIe (m.2) SSDs are faster than SATA SSDs. M.2 is one way to connect an ssd not the only way.