VCVRack > https://vcvrack.com/
Just download the linux zip, extract and launch the executable.
To add modules, you need to create an account and from https://vcvrack.com/plugins.html, add some modules then launch Rack, log in to your account, update the library and relaunch Rack. But, as VCVRack is now v1, you can only install modules that are v1 also, previous modules like 0.X.X won't work in VCVRack v1
This is a powerfull rack modular synthetizer, add many modules your computer can handle (set the block size to 4096 in the audio core module and keep the zoom to 100% as possible to save cpu & gpu and a very good tip is to set the frameRateLimit to 15 instead of 70 in the settings-v1.json file from the /home/.Rack folder, We loose precision with mouse interaction but that's ok, it's still tweakable (I set my to 10, that's ok)).
There is a lot of tuto on youtube, like Omri channel: https://www.youtube.com/channel/UCuWKHSHTHMV_nVSeNH4gYAg/videos
I'm addict now! 😀