I want to allow users to subscribe to categories. This documentation gave me hope, but there seem to be a lot of flaws I can't find ways to overcome.

1. The pop up shown in the docs there seems ideal, but after some testing I'm unable to find a way for a user to revise their subscribed categories without unsubscribing and re-subscribing.
2. The pop up ONLY shows up if you click the button provided at the end of the post, OR the button provided by the "floating subscribe button" option. There are several other ways for users to subscribe that don't display this pop up, and therefore don't allow category selection.
3. The floating subscribe button clashes with one of these alternative subscription methods which also floats in the bottom right corner and half covers the button that does what I want. I can't figure out how to prevent the unwanted widget that allows users to subscribe without choosing categories. Of course if clicking the gray subscribe popped up the category choice dialog that would be fine too and I wouldn't need the blue button (in the image below)

Does anyone know how to get this working smoothly without UI clash and without forcing users to unsubscribe if they decide the mails for one category were not as interesting as they hoped (risking that they never re-subscribe)

Although I am very technical, I have many other areas I wish to focus my programming skills on, so I'm looking for solutions that will not involve moving off of WordPress and deploying an instance with custom code. I'd also like to minimize custom JavaScript or CSS that could complicate upgrades. This site is meant to serve as a newsletter for my activities as a fantasy fiction author, so the focus is on push-emailing subscribers, and I'm not looking for ways to use RSS related features instead.

Edit: have confirmed that this relates to jetpack based on the CSS names I see on the blue button and a not very acceptable hack is to raise the CSS height (currently equal to the gray bar) like this:

.jetpack-subscribe-floating-button {
  position: fixed;
  z-index: 50001;
  bottom: -10px;
  right: -10px;
}

Which works, but then fails if the user has minimized this tool bar:

Also the user looses access to the three dots on this toolbar. Raising it above the gray tool means the user can choose the wrong subscribe option and hacking CSS to try to delete the wrong element is exactly the sort of thing that likely gets bungled on upgrade of wordpress or whatever provides that action bar.