Hide 'Filter' icon in Big Sur Apple Mail

Many users intensely dislike the inability under Big Sur to hide the Filter icon. All other tool bar items can be customised in position, or dropped.

I suspect these users are like me using the side by side layout rather than "Bottom Preview".

These users also dislike (rightly so!) the need now to swing their cursor a great distance to get to the tool bar icons, which are now centred right.

The following suggestion may not be to everyone's liking but may help:

The problem goes away if willing to try this combination:

Menu > View > Use Column layout

Menu > View > Show Side preview