custom-hot-corners-extended VS adw-gtk3

You can try Custom Hot Corners - Extended extension and set any monitor corner or edge to toggle Always on Top of focused window on mouse click.

Updated filters are also available as actions in Custom Hot Corners - Extended extension, where they apply on the currently focused window, instead of the whole desktop.

You can try Custom Hot Corners - Extended extension, the latest repository version can do that, I've just added this action. You don't have to use hot corners and mouse options at all, you can only use Keyboard page of the Settings window and set your keyboard shortcuts for actions you are interested in. CHC-E can do many useful things.

CHC-E extension can toggle dark mode for both at once, using a mouse or keyboard shortcut. The latest GitHub version also supports new Ubuntu accented Gtk themes.

I recently added actions for moving windows to adjacent workspaces to the CHC-E extension. It allows to register global keaboard shortcuts which work even in the overview. In addition CHC-E can move the window to the workspace which yet doesn't exist, if you try to move it in front of first workspace. It can also move all windows of the same application from the given workspace to another and also move them to newly created workspace in chosen direction.

Look into the "actions.js" file here: https://github.com/G-dH/custom-hot-corners-extended, where you will find requested js calls that work with GS from at least 3.36 to 40.1. The linked extension is available on extensions.gnome.org too.

Use this theme

As far as I know it doesn't exist yet... but most likely Evince will be ported in the future. But while that doesn't happen, what you can do is use the adw-gtk3 theme (https://github.com/lassekongo83/adw-gtk3) for legacy applications to combine with applications that are already ported to libadwaita

Why not use the adw-gtk theme for gnome to make all the deco's match rather than use Adwaita-Dark?

Application Theme : adw-gtk-3 with Gradience

You can use the adw gtk3 theme. https://github.com/lassekongo83/adw-gtk3

GTK theme: adw-gtk3

That's because i use this KvLibadwaita and adw-gtk3 themes to have everything looking the same on Gnome :>

Just found a workaround for the issue until an update fixes the issue for Fedora 28 - Alt+F2, type "r" to restart Gnome Shell. More info: https://github.com/lassekongo83/adw-gtk3/issues/213

I believe that adw-gtk3 could still be beneficial in ensuring a uniform appearance across both GTK3 and GTK4 applications. The more solutions we can offer to users, the greater the likelihood of achieving the desired outcome.