I found this, dynamicwallpaper.club searching for “macos dynamic wallpapers”.
Not sure what format they are in but recently ditched windows for Linux/kde and noticed KDE has some semblance of desktop wallpaper switching. I haven’t tried it out yet but maybe this helps out somehow.
Steam link for the lazy (like me)
https://store.steampowered.com/app/2379910/Dystopika/