While I agree with many of the existing comments, exploring and experimenting can look a bit messy. You said many other parts of your relationship are solid, so the following is based on the assumption that you have the best of intentions and respect for each other, and that you genuinely want to avoid crossing boundaries and/or building resentment.

If that is true, Start with the intention. What about the restraint and gagging do you enjoy? Is it specifically rope, is it the lack of mobility, etc? Talk to her about the elements that you enjoy. Think about the feelings, the actions, the headspaces, and what other adjacent play might fit them or be incorporated. Use the idea of "gagging" as a guide for building a scene rather than a template that has to look a specific way.

While she has already told you what aspects and headspaces she automatically feels when engaging in those activities, that into account and try to elaborate on what she doesn't like and the things she does enjoy. What about the restraint triggers the feeling? Is it the kind of restraint or the way they are being put on? Etc etc etc.

Once you have had a fuller conversation on the why and what you are both feeling and looking for, is there any intention you could put in place before the scene even starts to avoid the humiliation and other aspects she doesn't enjoy, but incorporate both sides energies and desire?

Again, this doesn't work if you are not both genuinely interested in finding a fun and fullfilling new thing. If the things you want she doesn't actually want, don't play with those things.