Meanwhile AWS is growing at 20%/year, Azure at 33% and GCP at 35%. That doesn't seem compatible with any kind of major cloud repatriation trend.
I worked at a very small startup years ago that leaned heavily on EC2. Our usage was pretty bipolar, the service was along the lines of a real-time game so we either had a very heavy work load or nothing. We stood up EC2 instances when games were lice and wound them down after.
We did use Lambda for a few things, mainly APIs that were rarely used or for processing jobs in an event queue.
Serverless has its place for sure, but in my experience it have been heavily over used the last 3-5 years.