If you remove Octiga do the (baseline) settings revert on M365
M365 client tenants can be updated by Octiga in a number of ways, including through baselines, user management, mailbox management etc.
Removing Octiga from a tenant will not remove any previously remediated settings which were made through Octiga.
Removing Octiga simply removes the Enterprise application (in Entra ID) through which Octiga can monitor and manage tenants