so i've done a couple of combination tests, here are the results:

Alone:
udp ipv4 - 🆗
udp ipv6 - ⛔ (but works after a tracker server restart) yet downloads
http ipv4 - 🆗
http ipv6 - 🆗

Dual:
udp (ipv4 and ipv6) - ⛔ (only ipv4 works, even after server restart)
http (ipv4 and ipv6) - 🆗

Both ipv4(s):
udp - 🆗
http - 🆗

Both ipv6(s):
udp - 🆗 (there is a thing, check notes)
http - 🆗

Ipv4 and Ipv6:
udp (ipv4) - 🆗
http (ipv6) - 🆗

Ipv6 and Ipv4:
udp (ipv6) - 🆗 (again, there is a thing, check notes)
http (ipv4) - 🆗

Notes:
major culprit is udp ipv6 protocol.
so it works after a fresh tracker server restart, but once udp ipv4 is used- doesnt work anymore (shows packet invalid size error).
this shouldn't be the case ryt?

and everything downloads file, even failed protocols alone. ig there is some in-memory stuff is going on, idk.
same applies for udp ipv6.

finally, file is downloaded, but the time taken is different, not speed, but the time taken to start download.
among these, udp seems slower. http is almost like instant.