Reading the thread from 2018 that was referenced in your 2019 top post of the current topic, it is clear that you misunderstood the earlier request, which has in fact been implemented. The 2018 request was for new login items created by the browser extension to set the item’s Name field to the FQDN (abc.example.com) instead of just the base domain (example.com), which was the original behavior. This was implemented (as promised by @kspearrin) in the next release, version 1.26.2 from April 19, 2018.
You (and @applepie) seem to be asking for a change to the way the individual URI fields stored within a login item are displayed when the item is opened for viewing its details. This is a valid request, but not that same thing that was discussed in the 2018 thread.
To avoid confusion, I have edited the title of your request (was: “Always show FULL URI / URL. Don’t truncate when saved”). To be clear, the URIs are not truncated when saved.
Finally, to add my own opinion, I would allow that it may be OK to display just the base domain (or host name), if and only if the URI match detection setting for that URI is “Base Domain” (or “Host”, respectively).