I’ve seen those messages but I’ve always ignored them. I restart whenever I decide, not when Mozilla wants me to. 😆

No. That’s the brainwashing talking. By keeping you scared about your security, all browser developers keep you under their complete control. And with that they impose their views on what your browser should look like/behave like. But most of the time they simply remove or change options - some are visibly removed/changed, others are either hidden or in about:config and are locked, so that you can’t use them or are just rendered inoperable. Security updates are just the excuse to impose their will on you. I had it enough of Mozilla’s constant chopping the browser off, so I moved to Waterfox which brings back all options Mozilla ever removed and then some. But by the time you remember that the browser is supposed to serve you, not the other way around, it will be too late.