Checking out an old commit is usually pretty simple in git, and can be done in a few minutes. But there is always a risk, that there is a problem with git, which might take much longer to solve.
With >> git checkout HEAD~3 << the third last commit can be checked out, use anther number for another commit. Use >> git log << to see check the last commits. git checkout takes also the hash id fo the commit you want to check out.
Meanwhile you check out a working commit, you can still work on the latest commit locally to fix the conflicts and any given bugs.
If the issue gets more complicated, also branches can be made to have a working live branch and another to fix the issues.