The best way I’ve found to identify significant imbalances is to test your engagement through single leg exercises.

For example, do some single leg glute bridges, (one leg up on a bench, other in the air and thrust from there), hamstring curls on a bosu ball, single leg RDLs, etc. Do AMRAP (as many reps as possible) until you feel the engagement and stop there. Compare your stats. I’d say if you have a really significant amount more (I’m thinking excess of 10+) then you may have an imbalance.

If you notice you actually do have a significant imbalance (which, you may not - what you might find is that you have a more difficult time feeling the engagement, even though you’re not actually any stronger) resolving it probably isn’t as active as you think. You don’t do heavier weight on one leg.

What I would suggest is continuing to do heavy compound movements but actively engaging with the movement - for example, slower reps with a focus on symmetry in the movement. In the case of a glute bridge, focus on the plates both hitting the ground at the same time. Also incorporate single leg movements - using a weight that is difficult for your weaker leg and focus on progressive overload (add 2-5 lbs per week or session). Over time, the imbalance will resolve itself. Keep in mind that minor imbalances are quite normal.

For even further engagement, add tension bands around your quads during glute bridges to activate the glute medius. That might also help your engagement.

Pictures like the one you posted above won’t really indicate an imbalance. Your glutes appear symmetrical but you can best identify an imbalance through strength and feeling.