Hi, OP. No offence intended here either but you are very unstable, and I would shorten your stirrups 2 or 3 holes until you develop a better base. Riding in extra long leather does not mean you are doing Dressage. If that mare does the smallest scoot you will be coming off. (Check out Lendon Gray’s “Lessons with Lendon.” It is a helpful reference for transitioning from H/J to dressage.)
The mare’s sluggy canter almost makes me question if this is deeper footing than what she is accustomed to. Strength training is definitely a place to start. Even walking random poles on the ground, building up to short cavalletti sessions.
