I worked at a place that just had a git on a sftp server and that was it. Worked well in a small team. Git is made for it.
Having a separate issue tracker turned out to not be a big deal at all. Theres a lot of niceties github has, but it turns out you really dont need a whole bunch to make good software.
Nowadays i would probably go with gitea or forgeo if I had to self host, but git by itself is perfectly fine.