Yes - that also goes for my earlier example of a shield set on Mountain King, or on Zelotah as in your case. But it doesn't go for the HP sets on your MK. In most cases, a set bonus is just a bonus - something that comes on top of the serious stuff if you're lucky, but isn't essential.  Having good crit rate on MK, however, IS essential. 

and spreading your good gear on crappy FW champs ?

What crappy FW champs? 

I don't have many champions. I have kept the best chamions, and I use the poorest ones as food.

The chamions that you see on the screenshot have me helping very well.

now 18. But get only tash 4 stars gear 😣

I cannot give my champions good gear. I have several champions that I don't have gear yet, because I keep getting junk and can't compete ' I will wait a while, if it continues in the same way, I better stop  

Seeing this comment and your screenshots, it looks as if you're selling all 4* gear as a rule and only keeping 5 or 6*? If so, that's a big mistake at your level of progress, you can do a lot with a 4* piece still if it has the right stats - doesn't matter which set it's in.