For those who use K18: do you condition/use heat protection afterwards or not?

I’m going to try it for the first time and unsure what is best. It feels weird to pile up a second leave in product (heat protector) afterwards but after all, they must have thought about it when designing the product ?

And is there really a use in using an extra mask/conditioner afterwards or am I better off taking advantage of the conditioning effect of the K18?

Of course I guess it depends on your hair situation and type… mine is neither thick nor super thin but I’ve lost a lot of density, and it is heat damaged.