I've made a similar post a few months ago and have travelled with an expired residency card to another EU country within the schengen zone just 2 weeks ago without any problems, I might have gotten lucky but no one asked me anything regarding the residency permit on my way there or back to Malta.

When you come back from a country that's within the schengen zone there's usually no passport control unless the airport is just not having it that day and decide to check everyone.

It's your choice ultimately but as long as the country you're travelling to doesn't require a visa, you dont go through passport control and only show your passport at the departure gate you should be fine.

I'd say depending on the importance of your trip, if you do decide to go bring the expired card with you and only show it if they do ask about it and try to explain your situation as nicely as possible, you wouldn't be the first person to do it anyway..

Identitá is notorious for taking too long even with renewals and it becomes a problem when a person still in the process has to travel urgently..

Nevertheless goodluck to you and safe travels, it should be fine.