Same issue.
I have 3 PCs / Windows 11 up to date, with latest Minecraft version 1.19.6201.0. If I start a LAN session, I cannot join.
I also have a version on an Android tablet. If I start a session there, my PCs can see and join the Android Minecraft session.
I have not changed my network/security settings recently.
Same here. All PCs can see each other without any change.