“As a theoretical state of being born “free”, as an individual, unconnected to anyone else you are perfectly free and self-reliant, although consequently thereby also subjected to the whims of nature and wildlife, as well as other people and societies. Speaking of ‘fundamental rights’ here is perphaps not quite as correct as speaking of ‘not having anyone restricting your choices’ in an pre-approved manner.
However, as soon as you decide to rely on others, as most of us have to, you will need to make compromises and give up some of that freedom, being given certain rights and protection in return, and all of it associated with certain obligations. All societies work this way, and any right you have in those are all dependant on the shared agreements made in those societies.
Ideally, if you don’t accept those agreements, you would have two choices; either work to influence those agreements, or leave the society altogether, to complete independence or another society more fitting to your views. Naturally, this is less easy to do today and leads to various issues, but theoretically we are able to withdraw into the isolation of the wild, or move to states closer to our views.
Fundamental rights and freedoms is still an agreement in society though, not something that actually exists outside of that, just like an animal in the wild doesn’t have “rights and freedoms”. Any animal can attack or kill another, and this without repercussions outside of perhaps a temporary counterattack from flock members.
There is no difference between humans and animals here. We aren’t born with any more rights than animals are, but like all flock animals we agree on certain acceptable behaviours and responsibilities, which together help protect us and make life for all easier. And we can choose to extend those rights and freedoms to members of other societies too, even to animals. Whole societies can act the same, and agree between them on the definitions of fundamental rights and freedoms. And it always inevitably involves compromise and restrictions of freedoms.