I am 38yo and regularly eat as much as 60g net carbs, sometimes more, and I have still enjoyed huge benefits from dramatically lowering my carbs, and increasing both fat and protein: more satisfying food, less sugar and junk cravings, less bloating, better digestion etc. It was quite painless to lose a few kgs and I am now in the middle of a healthy weight range which I am easily maintaining so far. I exercise (4 x circuit class per week and lots of gentle walking) but not as much as you. I eat onions, berries, carrots, tomatoes and dairy milk every day, and some beans or lentils most weeks. This carb level has been working brilliantly for about 4 months now. If it stops working, I know strict ketosis is there as a tool for me to use.
Since you appear to be a very healthy weight, obviously lead an active life, and say you are feeling good, I’d consider not worrying about your ketone levels. I know ketosis is a specific physiological state but I like to think of “ketogenic living” as a little bit more of a flexible spectrum, whereby you can subscribe to lots of the useful ideas and principles, and reject the general assumption that carbs are healthy (and perhaps be stricter, when you need to) but not actually worry about testing or even whether you are in ketosis. I know it would probably be defined as LCHF rather than ketogenic, but if it’s working, who cares? Certainly no-one on this forum.
If you already feel good, what are you “chasing”? You never know, whatever you might gain in the magical state of zero-carb fat adaptation, you might lose in terms of enjoyment and sustainability… I only say that to encourage you to enjoy where you are at, if it’s working for you. We are all on the same journey, as I see it: trying to figure out what macros give us the best success (and success is defined differently for everyone).