Thanks for the answer. I don’t know why, but with this modification, I was able to use my dongle with the alsa-midi interface, but there were lots of missed notes. And I found that the problem in the first place was due to selinux. Once this problem was solved, I was able to use the dongle with the pipewire-midi interface. Hence, I removed this modification of bluez.
But, as I’ve seen, using the pipewire-midi interface adds some delay. I’ll try to reduce the buffer size to see if it helps. But I may try again the modified bluez package just to try.
If your system is up-ot-date, you should try is it does not work with pipewire. The solution of my problem is there: