SUMMARY
When I open kile, a kioworker process is spawned (/usr/lib/kf6/kioworker /usr/lib/qt6/plugins/kf6/kio/thumbnail.so thumbnail  local:/run/user/1000/kileospGML.7.kioworker.socket), and it takes up around 2 GB of RAM.
Also, I get the following output on the terminal:
mlt_repository_init: failed to dlopen /usr/lib/mlt-7/libmltmovit.so
  (libmovit.so.8: cannot open shared object file: No such file or directory)
mlt_repository_init: failed to dlopen /usr/lib/mlt-7/libmltrtaudio.so
  (librtaudio.so.7: cannot open shared object file: No such file or directory)
mlt_repository_init: failed to dlopen /usr/lib/mlt-7/libmltsox.so
  (libsox_ng.so.3: cannot open shared object file: No such file or directory)
[mov,mp4,m4a,3gp,3g2,mj2 @ 0x564d6e9a7940] moov atom not found
[mov,mp4,m4a,3gp,3g2,mj2 @ 0x564d6e9a7940] moov atom not found

Now, if I uninstall mlt (a kdenlive dependency), the kioworker process only takes up around 50 MB. I can reproduce it even after clearing the kile cache and config files.

SOFTWARE/OS VERSIONS
Operating System: Arch Linux 
KDE Plasma Version: 6.4.90
KDE Frameworks Version: 6.18.0
Qt Version: 6.10.0
Kernel Version: 6.16.9-arch1-1 (64-bit)
Graphics Platform: Wayland
Processors: 4 × Intel® Core™ i7-7500U CPU @ 2.70GHz
Memory: 9 GB of RAM (8.2 GB usable)
Graphics Processor: Mesa Intel® HD Graphics 620