My husband worked at a place like this for a few years. But they were #2 or #3 in their industry within the US so a foreign competitor acquired them (then shut them down, of course with zero interest in adopting any of the amazing parts of their product or culture). He's had some success taking some of the things he saw to his next company. 🪦 RIP Tradesy.
His companies approach was to have an engineer be oncall an entire sprint, and it rotated. They were helping even with items outside their team / part of the product so run books were a must. They supported CS the entire time.
If there weren't fires they were responsible for addressing bugs, UX issues, adding automated tests, etc.