Is that rot? :((

symptoms -- mushy, smelly, pulls out easily from stem and completely -- not partial tear along stem etc... you'll know from that immediately.. also if it expands... you can try to cut off infected area... but it likely has already spread. it's really not worth it to smoke such things. but, you can try and if it doesn't become apparent elsewhere, it doesn't mean it is clean.. that's the problem. you won't know unless you take it under a scope and look for growth. heh, the leaf? looks a little shriveled. light too close? either way, if the material around it is firm, smells fine and feels normal otherwise, it's not rot. unfortunately the best way to know is to touch it.

Pic 1 and 2 definitely look like rot. It's best to cut them off and sterilise your tools in-between. Make sure not to let them touch any other part of your plant and keep a close eye on any of the other buds. I'm not sure how much you should cut off, perhaps someone could shed some light on that. When I had mold I cut it off a couple of inches below the mold on the first buds. Then I moved to cutting the entire affected branch as other parts kept getting infected. So personally I would cut the whole branch. You could try cutting the clean parts of the infected branch in a couple of chunks and let it dry to see if you could salvage some. If you really wanna use the moldy/risky parts, toss them in a container with a strong dessicant and a small fan. This will dry out everything ASAP and prevent the mold from devowering the entire buds. Then you can make an ISO extraction, run it through a 0.22 micron filter to remove the spores. This is what I did and it to my knowledge it should be safe.

Hi buddy difficult to recognize in the pictures but very difficult to imagine with a humidity of 35% :-) take a close look at it with a microscope 👍

Looks that way to me. I would immediately chop that bud making sure not to disturb it much, and if you want, chop it up afterwords and dry/cure whats left on its own. Some recommend not even using that bud at all.