Currently the iPhone toolbar has 6 possible options available (Delete, Archive, Snooze, Spam, Move & Read/Unread). My phone (iPhone 11) has space for 5 options. As there are more options than spaces available an ellipsis takes one of the spaces which leaves 2 options needing 2 clicks to use. Once you have clicked the ellipsis you can then drag-scroll the toolbar left/right to access the options.
Wouldn’t it be easier if you could just drag-scroll the toolbar right from the start? This would enable one more (at least) option visible straight away and save a pointless click. Maybe making 5.5 (or 4.5) options visible would show that there are more options available to scroll to.