Is this noise caused by a bearing?

[GabrieleItalia]

Good morning guys, I need your advice and help. I am the owner of a 2018 Can Am Spyder F3s with SE gearbox with 54000km, which I have always carried out maintenance on. I have always used fully synthetic oil, I also recently changed the H CM filter and the oil. I also replaced the front pulley with the new white one about 20,000 km ago and I no longer had any problems. Now, however, I have a strange noise coming from the left side, a metallic noise that appears only when I release the accelerator knob, and only while driving, while with the gearbox in n, this does not occur.
I have already checked the front pulley and its screw, but they are ok, I have checked the arms and they are ok, I have checked the heat shields of the mufflers and they are ok, I have checked the brake pads. Brake discs and calipers are ok. Shock absorbers ok, plastics ok, airbox ok. Tire bearings ok. I think it's the bearing, since I did a test by putting a hydraulic stand to raise the rear wheel and making it spin freely the rear wheel bearing was silent while I heard some strange noises coming from right behind the front pulley
I'm starting to suspect that it's the bearing on the shaft between engine and transmission.
I will talk to my trusted mechanic about it. Does anyone know if it's a long job, but still doable? I think I'll buy the workshop manual. And above all, if I included an exploded view of the gearbox, someone would be able to tell me the bearing codes. Also, should I also reorder a new screw for the front pulley or can I reuse the old one? Thanks and sorry for the bad English.