Thanks to @unfa and https://youtu.be/Ox9HiA9Wdlc?t=907 I made my first IR using LSP Profiler. The trick was to calibrate as my input was too quiet and the plugin didn't detect what it needed to detect. I saw the input meter jumping and I thought that was enough. Of course, my first IR is absolute rubbish, so I won't publish it, but in the following months I'll try to capture IR of my guitar cabinet. I hear it's quite rare sounding cabinet, so why not share it with the world 馃槂
For Unfa, a promise I'll do it with Open Source OS, and it won't be Linux. I hope you can forgive me 馃槂