I had the same problem until I installed the nvidia drivers. KDE will install some that gets things to work but I had that sleeping problem you mention. I can’t remember the exact package name but I can try and figure it out if you need help finding it.

Ya I also use librewolf and I find it fairly intuitive to start at a more hardened place and enable convenience as needed. Though these days I find most sites work great even with full fingerprint protection.