Ember safe 3' or 4" bathroom vent, for metal roof? 6:12 pitch

Is there an ember safe bathroom vent made? I'm in a Class A roof Wildland Urban Interface zone, and the inspector is asking for an ember safe vent, fora new standing seam metal roof.

The best I can figure so far is using a standard dormer vent, then using solid metal pipe back to the bathroom, fire caulked.

What might pass code, and work without clogging up over time?

The inspector, in that way of inspectors, is looking for a certification stamp of some sort.

Vulcan makes some ember safe dormer vents, but they don't naturally attach to vent pipes.

I would not consider a damper solution adequate as the only fire protection, as high winds are associated with wildland fire events. The vent would just flap open.

So, no I don't have an answer yet.

Any sort of pressure difference could cause the damper to open, admitting embers.

The ember safe vents have a baffle or fine screen to exclude embers, which of course could well clog with normal dust from a bath vent.

I don't see any options at https://osfm.fire.ca.gov/divisions/fire-engineering-and-investigations/building-materials-listing/

(The official list of WUI registered products).

Who would be qualified or experienced to work out this issue?

I talked to all three WUI certified vent makers, none of which does bath vents:

https://www.embersout.com/ - mechanical baffle also drains wind driven rain to exterior, good for gable vents.

https://www.vulcanvents.com/ - chemical expanding compound, toxic but maybe not a big deal when house is on fire.

https://www.brandguardvents.com/