They do, but just like anything dealing with security or privacy, there are degrees of inconvenience and "breaking" that are not suited for every situation.
Firefox is a good default, but if you want more privacy, LibreWolf is an option. LibreWolf configures more settings by default to protect your privacy— but these come at a cost. The cost being that more websites are likely to break and/or need "fixing". Look at the list of features that LibreWolf may break here [0]. This is not a browser for your general family or someone who just wants things to "work".
Interestingly, LibreWolf disable Google Safe Browsing, which they actually recommend you enable as Firefox has implemented it in a privacy preserving way. The devs disable it by default in LibrewWolf for a semi-technical reason [1]. Without Google Safe Browsing you will not get warned about dangerous sites known for phishing, malware, or unwanted software. Technically inclined people may not want this, but I would never disable this feature for friends/family as that would put them at risk.
Lastly, if your friends/family ran into website that doesn't work, they will not be troubleshooting the problem or trying to find a workaround. They will uninstall the browser and go running back to Chrome- this is the fine line that Firefox needs to navigate to ensure they protect user privacy, but don't inconvenience those who don't have the technical chops or patience.
[0] https://librewolf.net/docs/faq/#what-are-the-most-common-downsides-of-rfp-resist-fingerprinting
[1] https://librewolf.net/docs/faq/#why-do-you-disable-google-safe-browsing
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