This is probably not the answer you are going for, but ultimately, you can use either hydrogen or qtractor as a sequencer, but trying to make hydrogen sync with qtractor through transport is honestly more trouble than it's worth and you're better off exporting your results (midi and/or .wav) to qtractor if you insist on hydrogen.
I would instead suggest using a plugin on a MIDI track; you could use a fluidsynth frontend (like Calf Fluidsynth) and load a nice drum soundfont. You could alternately use the excellent drumkv1 application as a plugin. The only downside there is having to upload the .wav file you want to use for each drum sound and then save the preset. On the positive side, the drumkv1 app allows you to transpose the pitch, change envelopes and filters, and do a number of other things that you would typically have done on the instrument editor in hydrogen.
This is probably not the answer you are going for, but ultimately, you can use either hydrogen or qtractor as a sequencer, but trying to make hydrogen sync with qtractor through transport is honestly more trouble than it's worth and you're better off exporting your results (midi and/or .wav) to qtractor if you insist on hydrogen.
I would instead suggest using a plugin on a MIDI track; you could use a fluidsynth frontend (like Calf Fluidsynth) and load a nice drum soundfont. You could alternately use the excellent drumkv1 application as a plugin. The only downside there is having to upload the .wav file you want to use for each drum sound and then save the preset. On the positive side, the drumkv1 app allows you to transpose the pitch, change envelopes and filters, and do a number of other things that you would typically have done on the instrument editor in hydrogen.