Just asking: how long have you been using Arch and why? What qualities did you like in it?

Going from Arch to Debian is a huge leap. In my personal opinion, Debian is a great distro for servers or really really conservative desktop users, but it gets stale really fast.

Something in between both is ideal for deskop use, like Fedora, Ubuntu, Mint, etc.. The half year release schedule keeps everything modern, but stable enough.

You said in another comment, that stability is the most important aspect for you. I recommend you...

Fedora Silverblue

Why?

• Great update schedule (see above)
• Extremely stable. Fedora at it's base (already pretty reliable), immutable base (less bugs, since that's more reproducible and therefore easier to fix), also
• Atomic updates. You either apply a functioning update, or no update at all. If you update on a traditional distro and loose power, it is only applied partially and your system is borked
• You can always rollback with one click if an update isn't working as it should (e.g. screen flickering)
• Seamless updates. They just get installed in the background and when you reboot, the next image is already selected for you. I don't even notice an update and never get annoyed. I shut my PC off anyhow every few days, since booting takes just a few seconds on an NVME.
• Base can be exchanged with one command. If you run Gnome and want to switch to KDE, you rebase with one command, reboot, and everything Gnome related is gone and KDE is installed cleanly! Feels like a reinstall, but your user settings and data are all still there. You can also rebase to something from Project uBlue, which offers custom images, like a SteamDeck-clone, different kernels, Cinnamon desktop, and so on...
• Huge software repository. You (should) never install .rpm s directly to your system, you use containers. Flatpak is great, but Distrobox even more! You can access the AUR too if you want and use those apps just like natively.
• And so on