Don't make any rash decisions yet, give it a little time.
The group of folks willing/capable to work on these is small but the right people are out there. Southern CA is a dense area and there will be someone who can help you not far away, just plan on doing a little more leg work, and figure on starting a good relationship with whoever you do find, make it worth their time to do everything right for you.
How far are you willing to travel for work on this collectible, classic car you are seeking to get back on the road? FYI: of the folks out there who own these cars and don't perform the maintenance themselves, it is common to travel a significant distance to have upkeep/repairs done by an expert. Tom Bryant in Maine sees cars brought to him from many states away. In comparable/similar cases of other types classic vehicles requiring the attention of a "guru", this kind of thing is also commonly seen.
What I'm saying is that you can definitely keep your car and get it in tip-top shape but it might mean using someone a couple of hours away.
Have you contacted Josh / Yoshifab in San Diego? He has done several D24T builds.
How about member adamdrives on this forum, now residing somewhere in CA, I believe San Jose?
Forum member 745 TurboGreasel doesn't post here as often as he used to but is experienced with these engines and no doubt could help with the work if he could be persuaded to. He is near Watsonville.
Cast the net a little wider, and you have options.