why can't you print with flexibles ?

You have a direct drive extruder - that's the most important thing. Most flexibles print under 240c - so no issue with hotend.
They all also print best on unheated printbeds - well I always use an unheated bed anyway :-)

Just remember you have to go SLOOOOWWWW.

maximum 30mm/s and generally better to run at 20mm/s.
Retractions around 1.2mm at 30mm/s

You have to do everything slowly as the filament deforms easily, changing the diameter and effectiing the feedrate.

But there is no actual reason for not using it.