It is required to change the balun panel. Namely add border-radius, margin, padding.
The ballonLayout property is ignored when balloonPanelMaxMapArea: Infinity . How can I set a custom view of the balun panel?
https://tech.yandex.com/maps/jsbox/2.1/balloon_autopan - this example does not help, since the usual balun is generated at the marker position.
I saw such a solution, but it looks a bit crutch. Custom balun for a card