(This is a small thing, just a matter of saving a couple of clicks :-)

I usually keep my Next list sorted by Priority (or by Deadline, which is also really by Priority except for the rare few tasks with true hard deadlines at the very top.) This is the order I prefer most often.

Very often, though, I want to select tasks to do based on Context, for example find additional errands (which I have defined as a Context, not as a Tag).

Then, what I need to do today is click the "Group by" selector, then click Context, then select my tasks, then (sooner or later) click the "Group by" selector again and then click Deadline (or Priority). This could all be a little bit smoother (at least on the desktop and web versions), for example:

Alternative 1) Keep all the Contexts available also as "filtering Tags" at the top filter bar. (This would work in mobile versions, too).

Alternative 2) Keep the grouping options always visible as individual buttons instead of in a "Group by" menu. (There is plenty of space on that line.)

Alternative 3) Like 2 above, but keep the "Group by" selector as a default grouping - next time you visit the list it will be grouped in this default order, and the direct buttons are just for temporary regrouping. (Or the default grouping for each list could be hidden in preferences.)

Alternative 4) Like both 3 and 1 above - allow all of these.

Just some thoughts - no big deal :-)