I went from a 1x sram force with the same Praxis carbon cranks to a 2x GRX system on my 2019 Diverge. My first attempt included a 2x praxis levatime 2 chainring/spider swap in. The GRX FD handled the 2.5mm difference just fine. I doubt it would be a problem as i have seen a few reports of road FDs being used with GRX cranks without issue.
The problem I had was the chainring bolts to chainstay clearance. There was about a 2mm gap which I felt was enough, but after 1 ride I could see the witness marks from the chainring bolts rubbing on the chainstay. My ultimate solution was to buy the GRX 810 2x crankset. The 2.5mm outboard chainline worked perfectly and I no longer have any contact in that area.
Edited to add: Per Praxis the M30 bottom bracket cannot be shimmed over. I confirmed this when I tried and the BB bearings bound up.
I will say the Praxis chainring shifting was much smoother than the GRX. Even smoother than my roadie bike with full DA.
Last edited by Bryan C.; 06-04-22 at 09:02 AM.