Ideally the WEB-UI should start earlier in the startup process, not after the initial folder scans.
On some of my slower nodes (VPS) with large folders there is a delay of several minutes between starting syncthing and the webUI being available
It used to be like this. It was a major pain - you could talk to Syncthing, but it wasn’t in a state where it could give you any data back. It introduces a lot of complexity, both in the web interface itself, and in anything which talks to Syncthing.