The way the tech industry and legislation is going, there's no predicting what things will look like 5 years from now. Anyone trying to tell you anything else is just trying to sell you false hope. LibreWolf is here now, and it's good. Unfortunately, tomorrow never knows. As long as there's Open Source and privacy minded developers, I think there will be a privacy focused browser, whatever the tech ecosystem looks like. And of course, that browser will only be private in the context of governing laws and surrounding tech.
For now, if you're really worried, you can work in the present to advance the cause of LibreWolf and other privacy focused tools like @Tiritibambix@lemmy.ml suggested.