We have started mirroring Termux on ftp.fau.de, located in Erlangen, Germany.
The mirror is available at https://ftp.fau.de/termux/ so the sources.list-entries probably would be (can't test):

deb https://ftp.fau.de/termux/termux-main stable main
deb https://ftp.fau.de/termux/termux-root root stable
deb https://ftp.fau.de/termux/termux-x11 x11 main

rsync or http are also available.
We're syncing every 6 hours.
The server is currently connected to the internet through 25 GBit to the German National Research and Education Network (DFN).

One more note: We would have added this mirror earlier, if your Mirroring-Wiki-page contained more relevant info, mostly: how much space will the mirror use, and how much traffic is there to expect for a typical mirror. This doesn't need to be detailed or up-to-date, anecdotal info is enough, e.g.: "A full mirror uses about 25 GB of disc space (as of March 2023). In February 2023, on of our mirrors, foo.bar served about X GB of outgoing traffic. Note that this value can vary a lot, depending on (among other things) how many other mirrors are serving your geographical location."