I write that here because I found the answer after looking for it.
I migrated from Ubuntu 25.10 to 26.04 just recently, and noticed quite quickly that the sound was crackling. At first I thought my jack was badly plugged, but I could not solve it physically. I searched several things.
Finally I found a matching thread, but I am creating a new thread because it's been two years since the one I found: Why do I hear crackling sounds on Ubuntu 24.04? How can I fix it?
What solved it was, as explained in that thread's comments:
sudo nano /usr/share/pipewire/pipewire-pulse.conf
pulse.min.quantum = 512/48000
(I guess a sed command would be better) than
wpctl clear-default
systemctl restart --user pipewire
(from user space)
Then the crackling sounds disappeared immediately.
I restarted since then, they are did not come back since a few days, so I am posting this as an answer.