Is it possible to default to a host name instead of a search query on Chrome for Android?
If you have root on the device, you should be able to access and edit your host file on-device.  If you don't have root, you can still look into:

configuring something at the router level,
add site as a search engine (I know Vivaldi supports this), or
search for browsers that support &quot;!bangs&quot;.