Buttons in floating bar like in Classic

There is a usability problem (I think…) detected when migrating one of my ‘CLASSIC’ applications. In the first image (blue background) the pairs of buttons (edit/cancel) (submit/cancel)…appear in a floating bar over the data of the detail fields.
In the migrated version only appears (only in the mobile version) an arrow on the left to indicate (cancel/return). See second image. In the desktop version (…) not even this arrow is visible.
To solve this problem I have added a couple of buttons (back/edit) but when scrolling they are not visible (as they are not in the floating bar)…

I think that being able to handle buttons in the floating bar of a record is necessary (in some cases they appear, for example cancel/submit) but in this case they appear in the lower part of the bar, which is a usability design flaw.

captures…
Classic


Migrated