Between clinker facade and roof: hornets want to settle

Good day!
Last autumn, hornets began settling in a gap above the last row of bricks, practically right at the eaves point. However, winter intervened, so nothing further could be done for the time being. It is not certain that the insects will try again this year, but insect experts told me that it would be a good idea to seal this area to prevent new colonization. It is directly above the front door and would pose too high a risk.
How would you seal this gap? Of course, I could prepare a strip for each field and nail it firmly, but I think that the vertical joints between the stones would still allow the insects to enter. Probably, you would have to stick an expanding foam tape to the strips before installation.
Or should it rather be plastered over? If yes, with what? Although I wonder if there was a reason why we did not completely seal it back then. Possibly some air is supposed to circulate there. Maybe I will look for a brown sieve-like plastic mesh that I can tack at the top on the wood and then run down into the gap. But I don’t know if that will be enough...
Thank you for any good tip
Matthias

Doesn't anyone have an idea? I can't be the only one whose house hornets want to settle in...

Well, as you already wrote, the area should have been sealed directly with Kompriband. In your place, I would still try somehow with it now, although of course it is hard to reach. If it doesn’t work, you can consider further measures. However, it is advised against coming up with the idea of trying to work with silicone or similar.

I wouldn't do that either, especially since a huge amount would go in there. I probably have to cut a strip in the format of a roof batten (planed and painted) for each rafter space, glue swelling tape to the back, and then nail or screw these strips from below against the boards.

There are places on my house where bees or wasps also penetrate the swelling tape between stones and windows and nest there...

Then I’m unfortunately at a loss, and maybe one or the other will still come forward with good alternative suggestions :)

But if the compression tape is properly installed and seals well, the creatures shouldn’t actually be able to get through, should they!?

How is your roof constructed? Is that the only ventilation of your roof? Then you need a locking grille. But it actually looks too narrow for the "official" ventilation of the roof.