IFR student: circling approach struggles

All through my primary training I learned never to turn more than 30
degree bank in the pattern, and keep that ball centered. For four
years and about 230 hours I've flown by that doctrine.

Now I'm doing instrument and on circling approaches I'm learning that to
keep it close enough in on downwind and still get it around to final
lined up, I have to bank pretty steeply and sometimes even do slipping
turns to final. Plus I'm starting from an altitude about 400-500 feet
lower than the pattern altitude I am used to. so suddenly I am being
called upon to do steep turns in the pattern, sometimes uncoordinated,
and significantly lower than I usually fly patterns. I'm find it hard
to unlearn and as a result my circling approaches are all overshooting
final. So far I have always been able to get back to it while staying
coordinated and land with plenty of runway left. I'm finding myself
having an easier time doing that than banking more than 30 degrees in a
slip while only 300-400 feet AGL.

Did other IFR pilots have this difficulty in training and if so how did
you overcome it. Right now my plan is to go up to altitude and practice
slipping turns and just work at it with my instructor.