lovefromisrael Mullvad, IVPN and ProtonVPN are the recommended VPNs for privacy in this forum and other reputable platforms. In the first two you can block trackers via DNS with various degrees of control (6 individual types to turn on and off in Mullvad and 2 levels of strength in IVPN). If that is not enough, both allow you to use a custom DNS server. You could for example set up NextDNS and fine tune your blocking there, but you'll have to trust two parties with your internet connections now so it's generally not recommended.
I can't say how the settings are at ProtonVPN, I dont use it because in my opinion it's the weakest of the 3 regarding privacy (still top 3 though and the right choice for people using the full Proton suite). They might also support custom DNS.
You could use different user profiles in case you want some apps to connect via VPN and others via TrackerControl. As for why there's only one VPN slot available per profile, I assume it's part of the Android security model. You can only circumvent it by setting up a global VPN on your router(s), but it's a workaround that needs to be done on every router you use.