The five you mentioned can't be combined.

But there are ways to change properties.

3 Perfect gem (of any type)+1 magic equipment = 1 random magic equipment of the same type.

This formula allows you to get another magic equipment with the same probability, and the ilvl of the generated equipment is equal to the original ilvl. But don't confuse "ilvl is a definite number" in some formulas with "ilvl of synthetic equipment and put equipment is completely equal" here. Therefore, if you want to synthesize a super amulet with+skills, you should at least synthesize it with the super amulet that fell in the nightmare, not with the one that fell in the ordinary blood wasteland. You can use this formula to synthesize a necklace of +2 skills, but at least when your character reaches level 84, and the probability is very small.

In addition to washing the blue shield and stabilizing the armor.

It's no use.

It's too early for beginners to contact this

If you have three perfect gems, you'd better wash the oversized amulet.