Venting problem - need suggestions

I just purchased a large laser engraver that comes with an S8 AC Infinity blower/exhaust fan. The laser has an 8" exhaust port as does the blower unit. My issue is i can find 6" and 8" vents that mount outside but I cannot find a jblock mount that big to go over vinyl siding. Both of these vents are metal and have a flat mounting flange.

I've seen some videos where people just mount them to the siding and caulk around them, this looks terrible. These vents are also quite big I was hoping to find something more like a dryer vent in this size that would blend in more.

So I'm hoping someone may know of where I can get a j channel block for vinyl siding that will accommodate this size vent and if there is a vent thats not so obvious as this

https://www.amazon.com/Hooded-Wall-Screen-Damper-Galvanized/dp/B09P9W92RX/