I feel the same way. The new wave of remote work and, hopefully, the normalization of remote will mitigate against the bad effects of ageism. People seem to care less about working with a person older than them (and more about that person's skill level and merit) if they are not in the same office with them. Maybe that's because a lot of younger workers have bought into the idealization of the "young, hip, uber cool SV office" with skateboards, pizza, and ping pong and so if the older worker isn't in their office there's no "danger" of spoiling that vibe. But I'm only guessing here.

IME, it's much worse.

The compressed interview process means that after the usual preambles, you get <30 minutes to convince a zoom conference of 2-3 engineers that they want to work with you. It leaves no time for you to overcome prejudice and preconceptions.

Except it will hurt chronoligcally old people who have a much younger age-attitude. I feel I act more youthful than a lot of my (much) younger co-workers because I'm established, curious and not focused on the rat-race as much as them. My hobbies are youth-oriented and my kids continually expose me to magical things. How do I promote this in a world that becomes even more focused on instagram presentation vs. reality?

How so ? You still need to pass interviews.