https://truecharts.org/manual/SCALE/guides/getting-started#adding-truecharts
You can try the truecharts variant instead and enable the codeserver addon to access the apps files in a web editor.
So after its active you would go to (replace with your scaleIP) http://truenas.local:36107/?folder=/app/config
Just edit there watch the Changes happen in real time.
From your comments depending on how low maintaintance your other website is... you can probably host it via cloudflare pages and connect your domain to it.
https://pages.cloudflare.com/