sudo dnf install gnome-tweaks
Refer the adw-gtk3 repo
sudo dnf install adw-gtk3-theme
Now set the them for Legacy applications to Adw-gtk3-dark
under Appearance
section in the Tweaks
app
Visit gnome-look.org to browse system themes, icon-packs, cursors, GRUB themes etc. (might have to debug to get it working)