Is it a red flag if a guy is 28 and hasn’t had anything serious for 7 years?

Chatting with a guy whose longest relationship was a year long. He also hasn’t had anything serious in seven years. I asked if he has dating throughout those 7 years and he said yes but nothing to “write home about.”

I’ve never met someone with this situation. Thoughts?

No judgment just trying to be aware of red flags before I invest my time in someone.