Just came to say, I appreciate your emotionally intelligent and balanced take on your experience, where it would have been very easy to react and let emotions take over (understandably).
-> Use the basic Astro template for blogs. It is basically enough for a self-hosted blog needs. Using any of the third party themes/templates with a list of features has a bunch of disadvantages. It takes more effort to customize and upgrading to newer versions totally breaks the setup, sucking in hours of your time.
-> VS Code has plenty of Markdown Extensions. Markdown Preview and Frontend Masters come to mind.