`zola serve` not easy to get working from within a virtual machine or container

Zola version: 0.23.4

Setup: zola is installed in a (no-GUI) Ubuntu VM, running on a Windows 10 host. The browser used to test the website runs on windows. It accesses websites which are running on the VM via IP, eg. http://192.168.86.15:1234. There are no firewall or networking config problems, as this set up is used to access a plethora of other websites developed within the same VM.

Issue: it took an unexpected amount of effort to have zola serve working - ie. display html and css/js

1. running zola serve only listens on 127.0.0.1 - fair enough
2. running zola serve -i 192.168.56.15 fails with error "ERROR No port available". I tried many variations of this, changing the port, using the IPv6 address, running via sudo.
3. running zola serve -i 0.0.0.0 finally makes the zola listen on the desired IP address, but all the links to css/js are broken, as they are A) absolute (why are they not relative by default?) and B) pointing to 127.0.0.1
4. running zola serve -i 0.0.0.0 --base-url http://192.168.86.15 finally fixes the issue with the absolute links using the correct absolute uri

Could point 2 be fixed?

Ideally, links should also be relative by default, reducing the need to mess around with base-url (see the existing open issues about that)