wanting to try a GUI toolkit: needing some advice on which one to choose

[someone]

Yes, I know this is a question lacking a straightforward answer.

Requirements:

- desktop only: forget about support for mobile tablets whatever

- wide cross-platform support not needed at all: linux and/or 
some BSD distro like FreeBSD/DragonFlyBSD and that's all; don't 
care at all for the Windows platform.

- Wayland support will be a plus.

- HiDPI support will be a plus.

What I like/dislike:

- like a simple classical UI: favored over any modern one:

   - eg: my daily-driver workstation is running the MATE desktop 
configured as unobtrusive and minimal as possible and I am quite 
happy with it; needless to say I hate modern gnome and KDE 
desktops not to mention unity and family.

   - eg: hate the dconf-editor controls styles (GTK).

   - eg: like ClawsMail [https://www.claws-mail.org/] classic 
style.

   - eg: currently using the xfe file manager 
[http://roland65.free.fr/xfe/] (which follows the early Windows 
File Explorer design) which is written in C++ and is built 
against the minimal Fox GUI toolkit [http://fox-toolkit.org/].

- like fast native compiled fast responsive minimal apps; say, 
what used to be the common way back on the 90s; eg: Windows forms 
over COM ... fast instantly-opening windows (providing the 
program itself do not make them lag of course).

- dislike the way modern toolkits like gnome/KDE rely on CSS to 
render the controls making the toolkits heavy on resources; 
prefer more traditional ones, but this is not a requirement, it 
is my preference.

What I know so far:

- I assume using the FOX library will be more or less a 
straighforward process since it is written in C++; ie: no 
bindings needed at all ... am I correct ?

- using the GTK toolkit within D requires the GTKD binding 
library.

Any comments are welcomed, even any comments regarding anyone 
experience with GUI development within D, no matter whether the 
answer would be relevant to my specific question seeking a choice 
or not.