What’s the point in continuing?

BLUF: I’m not improving or retaining knowledge and it’s defeating to watch others blow by me. It’s not enjoyable or “humbling” as so many put it. Other than not admitting defeat, what’s the point in continuing Jiu Jitsu?

For context: I am technically a blue belt with about 5 years of training, but taking time off essentially means I’m back to being a white belt skill wise. I don’t grasp concepts easily, can’t remember moves, am unable to execute moves I do remember, and just not improving over time. Meanwhile, other people are doing just fine and I’m getting smashed constantly. I know everyone gets smashed, but given the lack of improvement over time and genuinely not enjoying it, I don’t see any reason not to quit.