I've just noticed that a year ago I was already trying this.
https://www.traccar.org/forums/topic/preview-modern-ui-with-secured-traccar-ssl-and-in-non-root-path/
I've put modern interface aside since then because of this problem.
There is way to remove it. Recompile the app with the root path and place it directly into the web folder.
Place the content of modern folder directly in web folder?
What should I recompile, the server or the react web interface? What exactly I need to change before compiling?
Place the content of modern folder directly in web folder?
Place the compiled app.
What should I recompile, the server or the react web interface?
The web app.
What exactly I need to change before compiling?
Nothing. You just need to compile it with the root path.
I use Traccar with both SSL and in a non root path as in here: https://www.traccar.org/secure-connection/
I'm trying to migrate to the modern interface, but I noticed that even it being the default now, there is this "/modern" added to the URL path.
This messes with the SSL/non root path config.
Is there a way to make the modern interface a proper default, with no "/modern"?
The configuration has this "web.path" but it points to "./web" as default, so the "/modern" is added by another thing.
It could be the opposite. If you want the old interface, you could put an "/old" or "/legacy" in the URL.