But... yeah. A colleague (25+ years) has to deal with this more than I do, but have hit it some over the years, and it happens more the older I get.
Often he or I may be 'right' but only because of existing constraints in a system. Someone with a different view may even be 'correct' in a nuts-and-bolts technical sense. Yes, A is 8% faster than B. But... we have an existing system in B that meets our current needs, and team who know B, have written it, and maintained it for a couple years. Switching tech stacks to something no one knows for an 8% network speed boost is not remotely helpful.
My experience was also that the young manager was very suspicious of the old fart. I've never had any problem working for managers younger than me; but some young managers don't know what to make of a team member that knows more than they do.
[0] No insult intended; almost everything I learned after the first 10 years, I learned from people younger than me.
In a start-up, having a team of young people will allow you to move fast, pivot and deliver. What you usually end up with though, is a tower built from spaghetti that's serving actual users. I see this again and again and then people get surprised that the software doesn't scale.