Wishing you luck in your new (old?) career!
I once rehired a person who had left us a year before. I heard through the grapevine that she wasn’t happy in her new position, and took advantage of it. She stayed another five years, worked out well.
I work in a fairly specialized corner of the oil and gas industry. I quit my long-term employer for a couple years around '99 or so, then got asked back for a different position. I didn’t have any particular reservations about going back. I can think of several people who have done something similar. In our cases, there are relatively small number of companies that do what we do anyway, so it’s fairly normal to leave, then come back (if one stays in the same line of work, that is).
Somewhat different situation, but I worked part-time for a company while in high school and the first three years of college. Seven years out of college I was unemployed and went back to work full-time for them. I stayed a few years until they ran into financial trouble and I was laid off.
I’ve done this. There are two companies that I’ve done temporary contract work for twice. I’ve also returned to a regular full time job at another company for a second time.
To make things even more interesting, I now work in the same building for my current employer as I did for a previous employer back in the 1990s!