> Being able to configure multiple VPNs at once, e.g. for Tailscale, ad filtering, blocking HackerNews during times when I should be doing something more productive

AdAway (in F-Droid) can block with /etc/hosts (no VPN involved) if you have root. The hosts blocking still works even when connected to a VPN. Aside from loading ad domain lists into /etc/hosts, it also allows you to specify custom domains to block - I personally have Reddit and HN in there :)