It's possible but eventually you will get banned I remember a torrent client that let me multiply my seeding by 100 I did use it back when file list was a thing.
That said I can't ever remember seeing anything similar since.
There is no reason that this should be possible on a private tracker. Public trackers, yes. Private ones need user authentication to let you download anything so it's trivial to track the ratio at the same time.
Filelist org while it no longer exists was a private tracker and I can absolutely say the cheating ratio client completely worked.
While I'm not proud of keeping myself ratio balanced that way (I had a very tiny upload compared to download) I can absolutely say a hacked uttorrent client kept me well above ratio at the time.
It worked well although I kinda glad I haven't seen similar mods sinxe