Drivetrain squeaky birdsong
I suspect the jockey wheels are the culprit.  You said you lubed the jockey wheels without removing them.  Likely the bearings or bushings didn't get lubed sufficiently this way.

Typically you will need to remove them and clean and lube the bushing or pry the dust shield off of the bearing so you can clean and lube the cartridge bearing (depending o the derailleur).  If you are dealing with a cartridge bearing you need to take  care when prying of dust shields so you don't damage them.

When reassembling the derailleur ensure you use loctite (blue 242) so that the derailleur doesn't do a RUD (Rapid Unplanned Disassembly) at a later point in time.