My idea BOB weight if I were on foot would be zero. Put it on a pack horse, a llama, a push bicycle or a 20 yr old companion with lots of brawn and not too many brains.

In my prime I hiked with 50lb thru the woods with no trail at altitude. It was exhausting.
In my prime, after I learned to reduce weight, hiking with 35# was much, much better.

Nowadays..... I can carry 25lb on hiking trails for 15 miles or so but I pay a price for it. A second day would be much harder.

Mostly it depends on your fitness. Thumbrules have assumptions that might not be valid for you.

I think I work with some people for whom a cup of coffee would be too much if they had to leave the building.....