Librewolf does that by default, among other things. And as thanksforallthefish mentioned, in settings you can whitelist some pages to prevent cookie deletion, if you want to remain logged in.

Sorry if these are stupid questions, but how safe is to use these apps? Can we get into trouble if we use them without a VPN?

can confirm

very kind of you, thank you :)

probably bc im stupid and didnt realize I have set it to turn wifi off automatically if it stays disconnected from any router for 10min

Is this why my GOS phone does not connect back to my home wifi every time i leave and come back?