Can't open Dolphin file manager from snaps

In code, code-insiders, and until recently, the intellij-idea-ultimate snaps, I have been unable to open the dolphin file manager when right clicking a file and clicking “Open containing folder” or “Reveal in file explorer” etc. Whenever i click these nothing happens. Furthermore, if I run snap run --shell code-insiders and try to run xdg-open ~, nothing happens. Additionally, opening a file using the default text editor (kate) with xdg-open ~/.profile for example doesn’t work either. Opening other things, like URLs work as expected.

journalctl -f gives this:

Feb 14 14:27:48 john-Desktop org.freedesktop.impl.portal.desktop.kde[2076]: xdp-kde-settings: ReadAll called with parameters:
Feb 14 14:27:48 john-Desktop org.freedesktop.impl.portal.desktop.kde[2076]: xdp-kde-settings:     groups:  ("org.kde.kdeglobals.*")
Feb 14 14:27:48 john-Desktop org.freedesktop.impl.portal.desktop.kde[2076]: xdp-kde-settings: Read called with parameters:
Feb 14 14:27:48 john-Desktop org.freedesktop.impl.portal.desktop.kde[2076]: xdp-kde-settings:     group:  "org.kde.kdeglobals.General"
Feb 14 14:27:48 john-Desktop org.freedesktop.impl.portal.desktop.kde[2076]: xdp-kde-settings:     key:  "menuFont"
Feb 14 14:27:48 john-Desktop org.freedesktop.impl.portal.desktop.kde[2076]: xdp-kde-settings: Read called with parameters:
Feb 14 14:27:48 john-Desktop org.freedesktop.impl.portal.desktop.kde[2076]: xdp-kde-settings:     group:  "org.kde.kdeglobals.General"
Feb 14 14:27:48 john-Desktop org.freedesktop.impl.portal.desktop.kde[2076]: xdp-kde-settings:     key:  "font"
Feb 14 14:27:48 john-Desktop org.freedesktop.impl.portal.desktop.kde[2076]: xdp-kde-settings: Read called with parameters:
Feb 14 14:27:48 john-Desktop org.freedesktop.impl.portal.desktop.kde[2076]: xdp-kde-settings:     group:  "org.kde.kdeglobals.WM"
Feb 14 14:27:48 john-Desktop org.freedesktop.impl.portal.desktop.kde[2076]: xdp-kde-settings:     key:  "activeFont"
Feb 14 14:27:48 john-Desktop org.freedesktop.impl.portal.desktop.kde[2076]: xdp-kde-settings: Read called with parameters:
Feb 14 14:27:48 john-Desktop org.freedesktop.impl.portal.desktop.kde[2076]: xdp-kde-settings:     group:  "org.kde.kdeglobals.General"
Feb 14 14:27:48 john-Desktop org.freedesktop.impl.portal.desktop.kde[2076]: xdp-kde-settings:     key:  "toolBarFont"
Feb 14 14:27:48 john-Desktop org.freedesktop.impl.portal.desktop.kde[2076]: xdp-kde-settings: Read called with parameters:
Feb 14 14:27:48 john-Desktop org.freedesktop.impl.portal.desktop.kde[2076]: xdp-kde-settings:     group:  "org.kde.kdeglobals.General"
Feb 14 14:27:48 john-Desktop org.freedesktop.impl.portal.desktop.kde[2076]: xdp-kde-settings:     key:  "smallestReadableFont"

I wonder if this is related to https://bugs.launchpad.net/ubuntu/+source/xdg-desktop-portal-kde/+bug/1822973

It seems that in Intellij Ultimate, dolphin is now hardcoded instead of relying on xdg-open, but the issue persists in VSCode. https://youtrack.jetbrains.com/issue/IDEA-197859

I am using currently kubuntu 19.10 with the backports PPA, though it has happened on other releases too.

I have found some similar questions

Any ideas where the problem might be? Is it a snap problem or a problem with xdg-desktop-portal-kde