I understood your situation.It is out of official procedure to manually embed PSC into VCSA for VxRail provided VCSA (a.k.a Internal VCSA). So, I highly recommend that you should rollback the PSC and the VCSA to those before your activity. If you take snapshots for them prior to work, it would be easiest way to do that by reverting those snapshots. File base or image base backups also would work fine. If there is no backups or snapshots, you are going to open support ticket to engage Dell support. I'm not sure how they handle this situation but my idea is, to redeploy PSC and VCSA  if possible, or externalize VCSA from VxRail and then get it back to internal one after upgrading to VxRail 7.x.
I used this article to try and run a python script to update VxRail, but the script fails. [URL]   The error message I get is - "The appliance is not managed by an external vCenter. Please check your environment!" Is there a script to use with an internal vCenter?
Unable to update VxRail manager after migrating from external PSC to embedded