When I replaced my Praxis bearings M30 threaded, they were creaking as well. I talked to Praxis and they were very much NOT on board with thread locker or such. They "highly" recommended anti-seize compound. I went to a copper paste version and it was much better.
I am sure thread lock will work fine though, lots of people do it. Each has its benifits but a good anti-seize should sold your problem...make sure its also torqued properly.
Good luck!