That’s the only strategy for similar internal versions of NC and OC (NC 12 and OC 10). For NC 13, this should be easier and a bit less dependend on the actual version. However, the migration app requires a specific migration path to be added.
For NC 13, the best is to ask a migration path in the repo of the migration tool:
Keep in mind that NC 13 has been released this week and a couple of things probably need to be fixed before handling the migration stuff. I’d schedule a migration to NC 13.0.1 mid-March (https://github.com/nextcloud/server/wiki/Maintenance-and-Release-Schedule).
If you want to test migration and check for problems before, I’d use a small test setup with similar config to your real setup. Manual migration should work (like a manual major upgrade: delete everything but the config and data folder, place code from NC 13, fix permissions and run occ upgrade from terminal).