KColorChooser, Pulseaudio volume control, Discover. These programs take a long time to open. I haven't had this on any Linux distribution (Debian, Ubuntu, Arch, Vanilla OS). Can this be fixed somehow?

Welcome to LXQ.

I assume that you're using KDE Plasma (Wayland)?

Running these commands can help with providing definitive information about your desktop environment:
With respect to KDE, please confirm if you are using "pavucontrol-qt" (graphical KDE UI). Not sure if the behaviour changes when a network is not yet up?

I assume that you're using KDE Plasma (Wayland)?

Running these commands can help with providing definitive information about your desktop environment:
With respect to KDE, please confirm if you are using "pavucontrol-qt" (graphical KDE UI). Not sure if the behaviour changes when a network is not yet up?
Yes, KDE, Wayland. Pavucontrol takes as long to start up as if the WLAN cable was unplugged.
Graphics:
Device-1: Intel HD Graphics 630 vendor: ASUSTeK driver: i915 v: kernel
arch: Gen-9.5 process: Intel 14nm built: 2016-20 ports: active: DP-1
empty: HDMI-A-1 bus-ID: 00:02.0 chip-ID: 8086:5912 class-ID: 0300
Display: wayland server: X.org v: 1.20.14 with: Xwayland v: 22.1.8
compositor: kwin_wayland driver: X: loaded: modesetting unloaded: fbdev,vesa
dri: iris gpu: i915 display-ID: 0
Monitor-1: DP-1 res: 1920x1080 size: N/A modes: N/A
API: OpenGL v: 4.6 Mesa 23.0.0 renderer: Mesa Intel HD Graphics 630 (KBL
GT2) direct-render: Yes

Ok, so KDE Plasma (Wayland) as I suspected. When you post commands and output, please enclose within [code]...[/code] tags (refer to the'# button) in the advanced forum editor.

With respect to your network connection, is is set as a system-connection or user-connection? System-connections (All users may connect to this network), the connection is made during boot, and before you log in. With user-connections, this only happens as you login to the desktop environment. Perhaps this influences what you are experiencing?

What's slow? Like painfully slow, or just noticeably slow - just enough to be annoying?

I recently did a clean install of f38 on a Celeron powered cheapo tablet. It runs fairly well for the hardware. I haven't noticed any significant slowdowns compared to f37 on the same hardware, and in fact even f38 beta blows Tumbleweed away which stuttered a lot and was slow. In all acses using Plasma and Plasma Mobile, with the typical KDE apps (Discover being one, which IMO has always been kind of slow to start, even on my ThinkPad).

When running a Fedora beta expect a little slowness, they do warn about it on the website, as at this point before release they still have a lot of debugging options enabled in the build.

My connection is system. For example, KColorChooser takes 25 seconds to start, Pavucontrol - 28. But I think I found the reason - I installed KcolorChooser from Flatpak. I removed it and installed it from the regular Fedora repository. Now it starts in 1 second. That's it.

goumba, do you agree that 28 seconds is a lot. On the same computer, in Debian and Arch, the same programs run in 2-3 seconds. I think it's because of Flatpak - its programs take a long time to start.

I notice a difference between FlatPak and native, but still, nowhere near 28 seconds. I do believe 28 seconds is a lot, for a trivial application like KColorChooser. Even with debugging symbols and build, it's a lot.

The tablet I mentioned is running Silverblue, so everything is Flatpak by deault. Even Chrome starts in less (albeit not by much) than 10 seconds.

Have you tried running them from a shell prompt and see if they produce any output? Perhaps it is stalling somewhere?

Update: April 2: Well, I'm starting to experience the same issue after an update to Silverblue 38. Starting an application in a terminal window indicates that there's a problem with Portals. It looks like some people have been dealing with it for a long time, too. Rebooting as suggested as the majority of the fixes does not work, on to other ideas.

Ok, so this happens on my tablet with Phosh and Plasma, but not with GNOME. It looks like something's not being set up right by the DE.