Copy modifiers + keeping those already there

hi guys.

so i have this dog, a buddy made some additional sculpt and rig on it while i made some muscle system on it.
now its time to merge it all.

copy vertex groups worked fine.
but i encountered an issue with the copy modifiers.

it just replaces everything already existing.

the documentation says that:
Currently behaves like constraints, all you original modifiers will be replaced by the ones on the active item.

so, what’s the workarround ?
how do i add and copy those modifiers ?

thanks guys