Properties is the widest panel among other panels in Illustrator.
While other panels by default have the same width (and some are resizable), Properties is too wide.

It gets specifically disgusting whet it get stacked with other panels — they have to conform the minimal width of Properties and start looking ugly.

At the same time, the main content of Properties does not look like it needs all that minimal width — there is a huge gap on the right visible in 'properties_1.png' attached.

Sure, when you have some art selected, it look differently, like in 'properties2.png'... but look at the 'properties3.png' — the Transform panel is not that wide in fact! It’s analog in Properties is just bloated!
Align section can be just reorganized (and include more options and ditch the dropdown, because Align has 3 buttons instead of it now), and this also applies to other sections as well.

The only problem is the Quick Actions buttons, which are two in a row.
Some languages use much longer words than English, and these buttons get even longer even, sure.
But it does not mean you have to bloat! Make them reflow and go stacked, when the width is not enough. See, you have a huge Recolor at the bottom, stick to that way!

Also, perhaps you want to remove gaps between all bottom buttons in the full Align panel, to make it have the same default width? It got changed when you made Align To options into buttons, and it’s kinda ugly. Buttons are great though!

This request originates form this bug report, about the unadjustable width of the Properties panel, when it’s stacked with other resizable panels: https://illustrator.uservoice.com/forums/601447/suggestions/32011942