Is it rot and should I cut it?

First time posting in the thread.

My euphorbia trigona is looking black (all sides) and soft to touch at the bottom.

I rarely water it to be honest, but from what I understand it looks like rot going up the plant, right?

Should I cut above the black area, let it callus and then replant?

Honestly, everything I've searched says I should do so, it's just that it would be my first time doing that, I'm scared and need some encouraging before I proceed.

Any advice is welcome.