Occlusion not working still not working ...

I searched for days in this forum, unity discord, internet, etc. Many people seem to have the same problem but I can't find a solution ...

My problem : I have a big problem with occlusion culling which doesn't behave as expected. Many objets which should be hidden are still visible. Another problem is that sometimes, visibility lines are totaly not logical.

My configuration : My scene is an interior scene with multiple rooms, few open places, and few corridors. I have tried all the values for the occlusion culling baking parameters, and I also set all my walls to occluders/ocludees and my objets to ocludees. All my objects are static. Since the occlusion culling is working a bit sometimes, I have the proof that all these objects are correctly marked as static, occludee, etc since they are hidden in some situations. I have merged my objects (for example one bed = 1 objet) to reduce drawcalls but now with this problem they are entirely shown in many cases where they should be occluded, so this optimization is totaly useless.

My main problem : -> Objects that must be hidden aren't , even if no visibility lines go to them : Example 1 : Example 2 :

My other problem : -> Visibility lines are not working as expected in some cases : https://zupimages.net/up/21/28/n9q3.png

What I have tried : I have double check everything and set the scene properly according to me. I also have tried occlusion area but I don't really see a difference (maybe i don't understand totaly what it is used for), but I have tried to put one big occlusion area including my scene, and I also tried to replace this big area by several occlusion area so that one room = one occlusion area. I am going crazy, I don't understand why it isn't working...

Can somebody help me ? Thanks a lot , I searched for hours and found nothing ...