As a word of encouragement to the OP, all of my family and my wife’s family retired here, with no problem. We’re in our 50’s and retired from the airlines. We have lots of investment properties and other consulting projects, plus family, etc., etc., that keep us busy, and we enjoy living in a place that has everything we want.
We’re in RSF and love it, and it sounds like you have received some great suggestions for possible locations in the price range noted. I particularly think La Costa might be a great fit.
As mentioned, it might be a bit difficult to get newer construction without HOA or MELLO, but there are certainly many options out there. Be sure to check out all zip codes of interest at sdlookup.com
It’s true that if you have to worry about money, whether you’re retired, young, old, or in-between, San Diego can be a difficult place to live the life you want to live. We’ve known many people–especially younger people–who have had to leave the state for financial reasons–but I don’t think that’s a problem for the OP.