Me too. I stopped and bought the tool that has two suction cups and looks like pliers. It allowed me to gently squeeze, release, squeeze and eventually it began to separate. Also, that tool kept me from pulling to hard or opening too wide thus saving the ribbon connections. The iFixIt heat tool worked better than a hairdryer.
I agree. Reassembly is NOT the reverse of the many steps! That ridge or plastic edge MUST be slid into first. Opening the iPhone doesn’t reveal that. Careful, because the waterproof glue can catch the battery cable too. Aligning the battery by connecting the battery cable/ribbon helps BUT be careful and remember to disconnect the battery BEFORE reconnecting the two data cables (Again, this would be obvious if the steps or reassembly pics were included. Number of steps = 60 more realistically because reassembly is just as important and risky!
No you can buy the replacement. See the above guide for a link on how to do that and iFixIt sells them. Recommend buying more than one because installation is tricky - must get it aligned perfectly though the spluger and pointy tweezers can help reposition minor slipups.