Scott you need a google account for this, which is an absolute no-go for people for whom privacy is important.
Those absolute statements won't be helpful here. Privacy is very individual and rarely "all or nothing". For example I use a throwaway google account to securely install apps on GOS via Sandboxed Play Store which is the best solution according to my personal threat model.
nman90 What other alternatives might there be if any?
My understanding is that for channel memberships you'd have to trust an app with your Google login data, which can be a security concern. I don't know any other app with that feature compared to what you have already mentioned, but how about using Vanadium or Brave with a shortcut to YouTube on your home screen? You might also use a Firefox based browser with add-on support (Mull comes to mind) to add sponsorblock or download abilities (but with serious security downsides).