Yep, full flex knife is the way to go. I use a Stanley knife, but I extend it all the way out, those separating blades are really flexible.

Glad to hear you are going well with it Serena, I've not said much in this thread, these guys prob have more experience than me with the Flashforge X, there does seem to be a fair amount different between those and the old one I've got.

As for stick, sorry, for me can't beat blue tape and PLA now...

Out of 3 machines, a kossel, prusa and FF, I get the same exact result with my PLA now and that is dead flat prints that will stick forever unless you pry them off..

Totally non heated bed, 200c nozzle and blue tape on glass ... and if there is ever a stick issue, I use a kids glue stick on the blue tape before printing. Best stuff ever. Best way to get zero corner lift from your prints all the way through the print.