suggesting to switch to slippy map when Nominatim request is too big

[A_Pirard]

I'm pretending to be a newbie.
For example, try to download Москва city.
The OSM server ... reported a bad request.
The area you tried to download is too big or your request was too large.
Either request a smaller area or use an export file provided by the OSM community.
Help does not help.
This occurs often.

Beside "too big" and "two large" seeming to say the same thing twice,
"smaller area" looks like obvious and the "export file" is sure cryptic.
But how to do the obvious?

I feel ashamed to have just figured after so many years that the slippy map is centered there.
So, what about the dialog suggesting to go to the slippy map and adjust the size?
Adding a button to do so, maybe?
And maybe, adjust the size automatically if it's possible?

Fighting against the JOSM reputation of complexity is made of this.
TIA !!!