Thank you for asking. PiHole is NOT just a filter. Especially not in v5.0, and certainly not with unbound. Of course, someone like you is aware of this. So I'm not sure how I should understand your "question"?
unbound is just another upstream DNS server, and does not affect the core function of Pi-hole. You can run unbound with or without Pi-hole, and run Pi-hole with or without unbound.
Chances are very slim. There's many ways to generate your own certificates. We don't have the time or resources to add external projects or add more code to maintain.
Being sarcastic to the moderators is not a good choice either.