SUMMARY
When using the search bar with certain search terms, kcharselect was hanging "forever" (I kept it on for a few hours).
On turning on logging, I found it stopping at :

___
qt.text.font.match: Family name match pass: Looking for family name 'Iosevka Nerd Font'
qt.text.font.match: QFontDatabasePrivate::match
  request:
    family: Iosevka Nerd Font [-- any --], script: 2
    styleName: Regular
    weight: 400, style: 0
    stretch: 100
    pixelSize: 13
    pitch: m
qt.text.font.match:   REMARK: looking for best foundry for family 'Iosevka Nerd Font' [1]
qt.text.font.match:           looking for matching style in foundry 'UKWN' 27
qt.text.font.match:           best style has distance 0x0
qt.text.font.match:           found smoothly scalable font (13 pixels)
qt.text.font.match:           found a match: score 4000 best score so far ffffffff
^C
___

Tried removing packages: extra/ttf-iosevka-nerd extra/ttf-iosevkaterm-nerd
Result: the hang reduced to a much more manageable duration.

STEPS TO REPRODUCE
1. Not sure, but do install extra/ttf-iosevka-nerd extra/ttf-iosevkaterm-nerd
    1.1. I had just installed all ttf fonts in the Arch repos
    1.2. Tried on another system with v25.08.1 (but not dumped all ttf fonts unlike this system) and unable to reproduce the bug there
2. in KCharSelect search bar, try the strings
    2.1. "lef" (I was going for "left")
    2.2. "rig" ("right")

OBSERVED RESULT
- You become unable to type further
- the displayed characters are not updated

EXPECTED RESULT
- user is able to type the whole search string
- the character display gets updated

SOFTWARE/OS VERSIONS
Operating System: EndeavourOS 
KDE Plasma Version: 6.4.4
KDE Frameworks Version: 6.17.0
Qt Version: 6.9.2
Kernel Version: 6.16.5-arch1-1 (64-bit)
Graphics Platform: Wayland


ADDITIONAL INFORMATION

1. Only started happening in the past few months, so might be related to some problem somewhere (maybe the font update?)
2. downgrading to ttf-iosevka-nerd-3.3.0-1-any and ttf-iosevkaterm-nerd-3.3.0-1-any seems to "fix" the problem