I've got an S23U. One thing I've noticed is when I've not opened an app for a while, an app update will often become available shortly afterwards in the Play Store. (Under ″Manage Apps and Device″). I think if the app is in Deep Sleep due to underuse, it skips the update check, or at least checks less frequently.
I also suspect if you 'chase' the updates by manually checking for them, you'll find them available sooner than if you wait for them to auto-update. That may just be logical, but I don't know if there's a technical explanation beyond that.