You mean your fet on times are sometimes very long or short?
Anyway, a good way is just to do a little flyback type high side isolated supply and reference it to the bridge node…in a full bridge do one for each side of the bridge.
Don’t put a y cap between pri and sec as it will just conduct huge pulse currents.
Put a third winding on the flyback and regulate that, so as to regulate the high side winding. Then you can couple your fet drive signal up with a digital isolator, or if you want the last word in transient immunity (100v/ns), then use the 1EDI20 by infineon.com
Don’t try and do two outputs from the one flyback because you will end up with the high dv/dt nodes being routed all over the place on the pcb, put the mini flyback next to the bridge node concerned.