Disclaimer: agency owner here!
Sorry to hear of your bad experiences with agencies… we have had many of those ourselves and that in part led to us starting our own about 4 years ago, but that is a long story for another day.
A great free resource: Facebook Blueprint. You can even pick up a qualification for the CV by doing it and sitting the exam.
A paid Facebook option: Jon Loomer – check him out for everything Facebook ads, he is brilliant and affordable.
A good group on Facebook (free): Facebook Ad Hacks
The best consultant on LinkedIn advertising: AJ Wilcox (find him on Linkedin)
Google support: Use the phone support they give you and ask for more. Usually this is great as start point to get your campaigns up and running.
Another option if you have not used it already is to look at the RBPN funding options for Covid support if you have not used it already for your business? Many agencies, ourselves included, have approved consulting services on offer that may qualify for up to 100% government funding.
Best of luck with your business and results going forward, it sounds like exciting times!