How to service/replace loud fan on a G-Technology G-Speed Studio drive

For a little over a decade, I have been using two G-Technology G-Speed Studio (thunderbolt 2) drives (16Tb) and these things are great even after all these years, however the fan has grown substantially louder, to the point I am constantly checking when it might die.

The fan it uses is an 80mm (measured), and I imagine it must be pwm based on its normal operation, but that's partially the reason I want to check it out.

I clean it every 3 months to keep the drives from overheating due to dust, and to extend the life of it, but there is so much abuse the poor fan will take with this thing constantly on.

I can't seem to find any tear down guide, and I would be saddened chucking it in the rubbish bin once something like the fan dies.

Has anyone had experience maintaining these devices? I would like to open it and perhaps change the fan (if possible). I have changed the disks once, and it feels this should be serviceable somehow.