I still don't understand how is this legal. Can any business put whatever ToS that they wanted to as long as it benefits them?
No, it is not legal at least not in Europe.
ToS must always be in accordance with the laws of the country where the business resides, you simply can't enforce terms that would harm consumer protection or rights. Anything in those terms that goes against EU laws is simply a no legal binding that would be ignored in any court of law.
I could, for example, create a business and stipulate in the terms and conditions that if you want to return a package you must first make a goat sacrifice and change your religion. Would that be legal? Of course not.
Also:
In no event shall Nexo, nor any of its officers, directors and employees, be liable to you for anything arising out of or in any way connected with your use of this Website, whether such liability is under contract, tort or otherwise, and Nexo, including its officers, directors and employees shall not be liable for any indirect, consequential or special liability arising out of or in any way related to your use of this Website.
This goes against an EU directive, it's about limiting rights to legal action and just like the others any judge in the EU will simply throw it in the garbage bin.