Thanks for reaching out.

We can add an extra condition to mention that outside the summer, the place is closed on Mondays.
https://www.openstreetmap.org/node/6979771440

There is an additional tag, "opennig_hours:kitchen", which gives detailed information about times where the kitchen is open.  But do I understand that between 10:00 and 17:00 the restaurant is open but they don’t serve hot meals, even during lunch time?

About the last remark, no worries: we shoud not mention such a level of detail on the map, this is just plain common sense that restaurants won’t let guests get in after closure time but won’t kick off existing guests.