No, I mean, if I want a website to not know who I am? Isn’t Brave or Librewolf with fingerprinting protection and a VPN a valid choice?

I think people shouldn’t be using Tor for daily usage. It just slows down the network for those who actually need it. It would be better if people donated to the Tor project or ran their nodes instead

Isn’t VPN a must-have to avoid IP-tracking without downsides of Tor (slow, Cloudfare etc.)?

Graphene OS - best privacy and security, only for Google Pixel phones

Calyx OS - less secure but supports cheaper phones (Motorola) and eco-friendly phones (Fairphone)

Honorable mentions are LineageOS, /e/ OS, Replicant and iode OS, however their security is much worse than of Calyx/Graphene (no verified boot), so use at your own risk

Yes, they exist, but there is no reason to use them other than tinkering around. Also they have much worse security than Android or iOS. So if you need something private and open source there are a plenty of degoogled Android ROMs.