Have you tried to introduce them while they are really tired?
When I started the in-glider introductions, I found they would immediately
grab each other and, what looked like a wrestling match, start to what
looked like intense licking/grooming. no hissing or crabbing.
I ended up taking my little boy and placed him outside of my little girls
pouch, he sniffed the pouch then walked in and went to sleep. I did this about 3 hour before normal wake-up. held pouch on my lap incase a problem arose. When boy woke up, I played with him then place him back into his cage for the night.