And, fwiw, I know several people who work on the services side and it seems like a never ending deluge of tight deadlines and one-off work that doesn't add up to deep expertise like an engineering role would. It's like sprinting a slightly different race month after month: you work hard but never learn the course or how to run it better next time.
Would be interested to hear if any solutions engineers have a different perspective.
I would say, the top maybe 5% of Sales Engineers/SAs (whatever you call them) do have a very deep expertise in one area and those are the folks who are trusted to get a deal done. I've done defense tech, adtech, and now databases. I've been the time to really go deep on databases and that's what I'm building my career around now.
The people I know got stuck doing customer conversions for an idiosyncratic power distribution management system. They learned some tricks to do conversions more efficiently, but they had very little experience they could carry to the next company (so they kept grinding many years for less than $70k / year)