I can tell you that age will not matter all that much if you look at rather rough, atypical positions like universities, city governments, and small/medium businesses (all unfortunately mostly not hiring right now). They could care less that you're in your 40s, but they'll try to hire you like you're in a different industry and do things like validating that you can use Excel, have people who don't know the position interview you, make you retype your resume 3 times to fill out the application form, and have obnoxious policies with respect to vacation time or retirement vesting.

Yes, positions aren't competitive, etc., but they mostly get really rough applicants and are happy that anybody who knows what they're doing applies, and are probably better than no work.