In my first post I suggested integrating the ease editor more closely into the Timeline ui, this would make adding and adjusting eases as well as visualizing ease presets much easier.
Also from the CC discord I know that people tend to not even know custom eases exist, as it is fairly hidden in the Project bar. (not being aware of custom eases would still be a problem with the suggestion, if the user is only using tweens. So for tweens there might be another solution needed)
Suggestion one: it is added to the Timeline as well as Keyframe properties. The ease editor would also preview the selected ease preset, but if you try to change a preset it would prompt you to (or automatically) create a custom ease.
visualization:
Suggestion two: same as above, but docked to the right of the timeline.
visualization: this is an example from Rive, with their very clean timeline. (this would me my favorite implementation)
Third option, Even though I am personally not a fan of it, I wanted to add it for completion as someone on Discord suggested it. This solution adds the eases into the Timeline itself, this might be great for eases flowing into each other, but leads to a very messy timeline that required alot of vertical space.
this example is from blender I think: