Buffets are a nightmare. Always.
My most conspicuous success was quite early in my pump career at one of those ‘all you can eat all through the afternoon’ places that we went to along with some friends in January this year. Essentially I bolused for a reasonably hefty meal 60:40 over 3 hours, but that was a deliberate underestimate of the likely massive carb load. I then added to more smaller boluses on top at something like hourly intervals (testing to see how things were progressing). That and the walk to-and-from the restaurant gave me better results than I’d expect to see from a scrupulously counted normal meal.
We’ve been back twice and I’ve tried to replicate that success. Unsurprisingly it didn’t work out so well the first time (I clearly thought I was immune to the buffet effect) but the second time was not too bad.