If you don't disable fetch.writeCommitGraph and gc.writeCommitGraph there is a chance that those operations will overwrite your commit-graph and delete the changed-path filter data. (fetch.writeCommitGraph uses the --split option so it might not actually erase the data until you have accumulated enough "new" commits)

You don't need to rewrite the commit-graph file every time you want to run "git log". The "git log" command will parse the newer commits the old-fashioned way until you reach the commits encoded in the commit-graph file. If you do it once now, then you'll still be fast even if a few commits are added on top of your existing history.

If you update the commit-graph with that command once a week, then you'll stay fast even in a very large repository.