Switch to a different program.
I use Pedalboard2 when I only want to realtime process audio on my PC and it works perfectly.
You would need to install Voicemeeter, Virtual Audio Cable, Jack or a similar virtual audio cables program for the routing and that's it.
Right now my audio processing chain consists of:
Input --> Satin --> DeniseBassXL -->TDR Limiter -->Panagement Enterprise Edition --> Output

And it only uses about 40MB of RAM and I get audio the way I want!

 

Thanks for the recommendations, but I'm not looking for different software right now. We can make a new thread to discuss system wide effects, if people are interested.


Anyway, I tested some more and I'll mention a couple of findings, also thanks to people on other forums with the same problem:
1. the sound comes back temporarily also by tweaking another filter in EAPO besides the VST, like a preamp.
2. the sound comes back permanently if another instance of Pro-Q is added in EAPO, even if it's then bypassed in the Pro-Q GUI.

The second one is an easy and effective workaround.

But generally speaking it looks like FF plugins have to be "interacted with" in some way, to not go mute.
I think this still points to a bad crack as the most likely cause. It could also be a bug from FF, but I think there's a smaller chance of that. And I see no reason why EAPO would cause this, seeing how it works fine for the first 30 days.

I hope R2R (and CE-VR and others) are aware of this, maybe fixing it is easy.

I know Equalizer APO isn't very popular as a VST host, but still it has ~50k downloads per week and I found several people complaining about this problem.

 

I just realized that there's another version of the FF bundle, released by an Anonymous cracker on Audioz. "FabFilter - Total Bundle v2023.02.06 [x86 x64 VST, VST3]"
This one actually works and does not timebomb in EAPO!

And that might explain why @Lieglein didn't have this problem. He probably installed this version (which is the first result when searching for FabFilter) and not the R2R version.

So this confirms 100% now that the problem is the result of a bad crack. R2R and CE-VR should take notes.