IF the governments start banning the use of cryptos all over the world If a global financial crisis comes and cryptos start to plummet how will NFTs handle themselves will they also
Yes.
Can Governments interdict the use and existence of NFTs? Do NFTs have a shadowy construction like Bitcoin which might get banned for being anonymous and used to buy drugs or other illegal things?
First and foremost, Bitcoin is not built with "shadowy construction". And Bitcoin is pseudonymous, not anonymous. Also, it's not merely used to do illegal things. Regarding NFTs, NFTs that are stored in centralized services might be ceased.
can they be still functional and governments can`t do much about it?
Some NFTs are built on top of a fragile platform. So it is not really decentralized and the government can do whatever they want.