Thx, so I researched it a bit; so Z-hop means little up-and-down movement between the parts and “support” is literally an extra part independent from the main part, used for support, if I understood correct.

I watched the video again and it seems that the problem is not due to the foot falling, but in the part where the two legs join 🤔

I kindly disagree, I only add supports when there is an angle bigger than 60°. It depends on the printer, I tested mine and 60° is the limit.

And about this video, now that I think about it, maybe the octolapse or whatever software that made the video probably touched the piece when it got into place for the screenshot, and made it fall.

Ironically if the video was not taken, the piece may have come ok.