Hello. Fabfilter works great in Ableton in HDPI mode! I got both. Cubase and Ableton. And I need to say, that Ableton works amazing on Windows in HDPI. You can scale it as you want and all looks smoothly and clear. Regarding Cubase honestly it’s so buggy! 
And it’s not regarding the third party plugins. I am talking now about stock Cubase graphic issues! Stock! And it makes me sadly. Come one, Steinberg! The end of 2021 is here! I was added another graphic issues on my topic here: