I decided to test out VictoriaLogs to inject logs from various sources, one of which is VyOS.
It listens on port 9428

I put in the following config:

[edit service monitoring telegraf loki]
tim@ferrari# show
 metric-name-label VyOS
 port 9428
 url http://192.168.0.5/insert

But this is what's generated in the telegraf.conf file:

### Loki ###
[[outputs.loki]]
  ## The domain of Loki
  domain = "http://192.168.0.5/insert:9428"
  metric_name_label = "VyOS"
### End Loki ###

The port is being inserted in the incorrect place.
If I delete the port command and try to manually set that URL:

[edit service monitoring telegraf loki]
tim@ferrari# show
 metric-name-label VyOS
 url http://192.168.0.5:9428/insert

We still end up with the wrong config as the config generator is still adding the default 3100 to the URL:

### Loki ###
[[outputs.loki]]
  ## The domain of Loki
  domain = "http://192.168.0.5:9428/insert:3100"
  metric_name_label = "VyOS"
### End Loki ###

It seems to me the url command isn't expecting/looking for anything after the hostname.

The only way to make this work is to manually edit the telegraf.conf file and HUP the telegraf process.