Where I am now (Seattle area), it isn’t really seen as a that big of a red flag. I always had good reasons for leaving. Other than 2, I’ve tried to never burn bridges intentionally and was even a rebound employee at 1 place (never tell HR during your exit interview what you really think of them).
I grew up in the South and moved back there for a brief period of time. It was very hard to find work down there because they called me a “job hopper” (which I was/am). I was asked several times “You’re going to give me a year and then be gone. Why should I hire you?”. Never had a good answer when I was in my 30s. Now that I’m in my 40s, I have a pretty good one.
That’s been my experience. I’m at a place now where I can see myself staying for awhile. I’m not curing cancer or doing machine learning or scaling things to gagillion requests per second. But I like the people, like my boss, and the problems are meaty enough to engage me during the day, but not so complicate that I work on them in my off hours.