One improvement you can make from a code design perspective would be to modularise your JS more.
For example, you currently have one file handling your server and db connections, your routes and your specific db queries. You can separate these concerns by having file that serve these purposes individually.
This can make it much easier to track where everything is in larger projects.
Thanks, I guess since I am more the hobbyist than a strict coder I don’t pay much attention to code design. It’s not as if I’m developing complex systems with a team. I tend to avoid using “over engineering” for simple projects. Since micro-services, by definition should typically only do one thing, they lend themselves to certain simplicity. But I’d concur with your comments for more complex and/or projects one would turn into a product.