A text field can have a round shape in the context of buttons, but making them both equally round would be a departure from tradition which is usually to differentiate text-entry components from buttons. Any time we depart from norms in UI we are taking risk and sometimes it can be rewarded.
In the context of an email application users will no doubt adapt to ...
What about multi select chips?
Choice chips are a compact alternative to checkboxes, it allows users to select multiple options, they are best used for one to two short words or numbers. It also provides clear visual input to users depending on each state to indicate what has been selected
The tracking of a dirty state and removing it if the change is nullified can certainly be done. I find it very useful myself; it saves my sanity and OCD anxiousness / mental load that otherwise arises if I see an "unsaved" indicator or dialogue box when I don't think I've made any changes.
To take VSCode as an example, you can see it does not ...
A couple of points are worth mentioning here.
Firstly, the general consensus is that disabling buttons is bad for accessibility reasons https://www.smashingmagazine.com/2021/08/frustrating-design-patterns-disabled-buttons/ it can be done, but personally, I'd aim to avoid it.
Secondly, in terms of a dirty state changing from and then back to the original ...
Best practice would suggest you avoid more than one row or column as it creates too much cognitive load for the user.
Re the answer above, neither sliders nor radio buttons allow for multiple selections. If you need users to select multiple values from the list then checkboxes is the correct design convention.
The problem I see using checkboxes is that while it allows choice selection, it does not offer a visual representation of:
The type of action being performed
The value increasing
The start / end location of the selected values
There is a Moodle plugin that allows to select steps in an intuitive and visual way within a progress bar:
With an adaptation of ...
Should I arrange them left to right instead of top down?
The right answer depends on the user's feedback and should come out from an A/B testing or usability testing result, if possible. Typically in the mobile device, we're used to for both horizontal and vertical direction, but that's also dependent on the real-state that is present there along with other ...