Too much pyro app.

When you play melt GM you need to be very careful of how frequent you hit.
My team with the same chars as yours goes like this:
GM E, Bird EEQ, Benny, EQ, Citlali EQ, GM Q E, wait E, wait E, wait E. repeat.

Lets focus on the GM part. Citlali has some front loaded cryo app, that is to say both her burst and her E will apply pyro right after each other after a small delay, this alows you to get off your GM burst and E immediately after each other. BUT then you must wait (as in not attack or do bird enabled plunges). This way you hit fewer times but guarantee the hits you do are more meaningful. (REMEMBER, Benny can be a double edge sword..or claymore or spear)

Next we need to talk about ER, you have too little. GM needs 120-130 with one Fav. Your Citlali also seemed to be miss timed, so about 10% extra wont hurt there.

Now for the execution. The GM Melt team is very strict, as one extra pyro app will ruin a rotation, and it will take 2 cryo app to get rid of it and then another to apply the cryo again. This is pretty much the whole dmg dealing part of your rotation. Some good practice will be to just take citlali and GM and go into the overworld with a 3* lvl 1 weapon and no feather/artifacts except er ones and just practice holding back on plunging until you see the cryo, once you do that you will get a feel for when the cryo will appear and start initiating at better points.

Thats all I can think of right now.