I used Qubes OS for quite some time and was satisfied but it really is a very heavy operating system. Think of having a desktop on which you have a lot of isolated virtual machines running. It requires enough ram memory to run at a satisfactory rate as well as you have to look which laptop is compatible. It is a very secure operating system by default, but I find it stiff. I went with something different that really works everywhere and is if not the most secure system one of the most secure. OpenBSD and I really will never go back to linux ever again. I could write a lot but they have excellent documentation that is really worth studying. I suggest you try Qubes OS if you have a compatible laptop or computer. I see in previous comments that Tails were mentioned. Anonymity does not imply a secure and shielded operating system necessarily. Anonymity is one thing, security by default is other. In general, check what suits you best.