Similar to the Spectacle issue that I posted here on the KDE Discuss forums, which I cannot link, because I can’t place links in my posts yet.
Firefox can take too long in saving image files. Especially larger ones. This seems to be a problem with how the program interacts with xdg-portal. Firefox hangs for a second when downloading an image through right-clicking on a full-sized image in pixiv as an example.
My specifications can be found in the thread linked, but I will re-list them below:
AMD Ryzen 7 9800X3D
NVIDIA GeForce RTX 3060 (12 GB)
48 GB of RAM
2 TB NVME SSD
Distribution: Arch Linux (EndeavourOS)
Kernel: Linux 6.18.7-arch1-1
Plasma: 6.5.5