This SO post goes into how to use git checkout --orphan to create a new branch whose history is totally separate from the "main" one. This other SO post shows how to do something similar with Git ...

Did you create a new Git branch? Need to push that local Git branch to a remote repo like GitHub, BitBucket or GitLab? This example shows you how to git push new local branches remotely.

Choose this option to create a new, blank Git repository on the GitLab server. Teams of developers use a Git repository to perform the following tasks: Track their files and their commit histories.