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Apologies you had a bad experience. There's no doubt the original App Engine had some... quirks. You may want to take a look at Managed VMs. All of the new runtimes are based on Docker images, are entirely extensible, and don't require the use of the original App Engine APIs: https://cloud.google.com/appengine/docs/managed-vms/ You can use whatever Database or NPM modules you want.
It's great to see App Engine getting better! I'm exploring it again after trying the original app a few years back and am enjoying the improved interface and abundant documentation and tutorials. One suggestion: Make a cloud storage product option free up to a few megabytes for hosting small personal sites. Maybe it exists already but I haven't found it.
There are a ton of options on what you can achieve inside the free tier. But the simplest one for the use case you seem to require is to author a static html site in a good WYSIWYG html editor and then deploying it as a static site in GAE.