I would make her go slow if she’s going to fast and when she goes to slow make her gallop around... Also I would make her flex her head and also make her frame her head/ be on the bitw
Vary the pace within a gait. If you are walking and she is unfocused, ask for a faster walk. Or ask her to stretch down. Same at the other gaits.
Give her something specific to focus on, such as circling, bending, lateral work, etc. Use half halts and transitions.
Pull and tug she will pay more atte
I suggest going back to basics and working on small circles and voice commands and if she wants to look at something than stop her and let her look at it for 10 secs and once she looks away or blows out pet her and keep going.
I always talk to my horse when riding, such as good girl. Maybe try just a walk in the field or arena (if you do hacking) and work on keeping her attention on you.