Latency is a deal-breaker for me, and this is where autocompletion engines generally introduce surprising user-interactive pauses. I've generally settled with using mksh (or OpenBSD's KSH depending on the environment) with little configuration outside of aliases, variables, and few local functions. I'm not left with this inkling feeling like accidentally running find(1) over an AutoFS file system backed by NFS that needs to authenticate, mount, and then run the operation.
When I need something more sophisticated, I lean on using Go or Elvish and potentially delegate some UI elements out to https://github.com/charmbracelet/gum.
I'd rather keep my shell simpler and delegate out any other complexity to these other programs. Autocompletion and these other features simply aren’t free.
Although, it might also be a hat (2nd pic on https://civilisable.com/traditional-swiss-clothing/ )
Note: That link's (actual) photographs seem to suggest that the topic was not adequately researched or generatively produced.
Namely the photo with the caption "The Origin of Swiss Traditional Dress Photo by Cabinet Card Gallery" contains a sign within some words that indicate that even though these are Swiss people in the photo they are actually wearing costume to celebrate Austrian traditional costume of the region of Styria. The hints are "Steirisch" (Styrian) and "Buachstoana" (looks like a phonetic spelling of a Bavarian/Austrian dialect word as opposed to Swiss German and "Verein" (club/association). If someone could expand the "erh." abbreviation in a period-correct way, that would probably be definitively telling. This also doesn't resemble much of the Tracht I have seen worn at festivals in Switzerland either (regionalisms aside).