Comment by mistersquid

The only hard part is securing your server, since setting up a remote git server only requires two things:

1. Running git.

2. Providing SSH access.

But even securing the server is not necessarily difficult, depending on the level of risk acceptable for your purposes.

Put another way, reasonable security is not too hard and AWS makes reasonable security fairly easy. Even self-hosted *nix servers can be pretty secure. However to seriously harden a service against skilled and determined attackers requires an experienced team and even that may not be enough.