Postgres server changed or deleted after Mac OS install

Today, I updated Resolve to the latest release. When I open the project manager, I see my 2 Postgres databases cannot be connected. I assume the server is not running or the Resolve installation has been corrupted in some way. This may be the result of a disk cleanup or it may have happened as a result of a 'clean' MacOs reinstall.

There are no Postgres processes running currently; there are Postgres folders in both the /Library hierarchy and in my Applications folder. They are both version 9.5.

I've read some posts about deleting the two folders mentioned above and running a shell script command. And then running the Resolve installer in 'custom' mode -- not sure how that is done.

My concern is the two pre-existing databases: I don't want to do anything that deletes that material.

Can you please give me a fairly detailed procedure that gets Postgres running again and with connections to this content restored?

Thanks for your help.

Following on from my first post:

I think the launch items relating to Postgres were deleted during a system cleanup so the server is not running. I'm not clued in enough to be sure, but I think that means the Postgres code is likely still in place along with the Resolve databases.

If that's the case, it should be possible to start Postgres manually and get the sql databases back on line. Alternatively, the launch items could be reconstructed and put in place. I don't know which is the more straightforward way to proceed.

What I'm thinking is, given this is a MacBook Pro, once I can access the sql project DBs, I will re-backup and migrate these to file databases and then remove the sql versions.

Is there any reason Postgres needs to be running for general, non-projectDB, operation of Resolve? I can use the overhead those processes are consuming for other things.

Will the manual provide me with everything I need to test this out and get it done?

Thanks for your help.