Flips in both FPV Freerider and Recharged are very slow--almost Slo-Mo. The rolls are just fine. I am using a Taranis X9D with Windows 10 Pro on a with i7-4930K w/32 GB G.Skills DR3 CL10 memory and an MSI 1070 Armor 8GB OC GPU.
RC Quadcopter Racing Simulator · By
Flips and rolls should behave the same, they use the same rates.
It might have something to do with your calibration, perhaps you aren't getting the full stick input reading on the pitch direction. If you go to the trim settings screen (Click "Calibrate Controller" and then "Go directly to trim settings") you should see if the stick input behaves as expected, that is, that you're getting the full throw on all axes.