The biggest problem with many of these legislations aren't how they affect big social media companies but small ones. In the UK for example it applies to any internet service that contains user-to-user communication, meaning even a site like NeoGAF would be operating "illegally" there for not complying with these age verification measures. Even worse, some legislators (probably due to pure tech illiteracy) even wanna hold services responsible when users bypass geoblocks with VPNs or the like (in case the sites don't want or can't implement age verification).
Big tech is the least affected by all this, it's precisely smaller sites and apps that will have problems. Only hope is for them to focus on the major companies while turning a blind eye for others, which thankfully does appear to be the case in some places like Australia who developed a specific list of services that need to implement this stuff.