https://www.youtube.com/watch?v=ogexnfng_hE&t=515s
The new runtime is 100% idiomatic without any special apis. We do offer certain native libraries pre compiled system libraries (to support headless chrome among other things) and certain ENV Variables for gcp API tokens.
You should be able to lift and shift a GAE Standard Node.js app to any other provider with minimal overhead.
I can't make direct promises regarding the runtime update cadence, but I can promise that I work closely with the people responsible for this and they care a lot about getting updates out in a timely fashion. The new runtime stack makes this easier to do than previous GAE Standard runtimes.
(Disclaimer: I work for GCP)
By contrast, I deployed an app on Digital Ocean and, though they have a solid product, I eventually shut the instance down to avoid paying the monthly fee on an app I rarely used.
And you should stop telling others what works best for them without knowing anything about what their projects and needs are.