Openvpn is slower than wireguard as you say, but i'm pretty sure I previously seen max my connection out at 20-30MiB/s before, in earlier VPN subscription, so millage varies(and maybe because UDP in openvpn), but wireguard preferred if possible of-course.
The incomming socks5 support, was removed in libtorrent 1.1.13 I believe, because didn't work in practise, because as you say the BIND semantics, and was just a test, which failed. It wasen't about privacy though. It still works at times for utp, pex and dht obtained peers, because retains your udp port, or something, he stated when I asked him about it once.
I haven't followed libtorrent development so much lately, but now see in changelog that e.g. in libtorrent 2.0.8, but not sure if unrelated:
"support incoming SOCKS5 packets with hostnames as source address, for UDP trackers"
Also:
"improve compatibility of SOCKS5 UDP ASSOCIATE", as I remember you mentioned before problematic I believe.
Anyway, above irrelevant now for you of-course - kudos for your project and work again
