I've worked less than full time for a good portion of my career -- sometimes salaried, sometimes on contract. If you can make it work financially, I highly recommend it. I can do unrelated personal work at a much higher level when I have 10+ hours per week available to advance it. And my energy for the "day job" is at its best when it doesn't eat up all my time, so my results per hour are better.

The pattern is rare enough that there is a cultural barrier, at least in the US (and possibly worse elsewhere?). I accept that there will be fewer opportunities, and plan to do outstanding work during the hours I'm engaged. My employer gets a happy me and benefits from (by now) decades of experience. I hope that more tech (and non-tech) workers will join me in advocating for this sort of arrangement so it becomes more common.