I believe AndreasV gave the answer on the discord server.
And I quote him: “Tunee, completely officially and never hidden, used the Suno 4.5 API.”
So Tunees have a smart chatbot that helps you talking to Sunos music creator, so when you upload musicpiece you do get Suno to make a cover for you. And Tunees chatbot is smart and make the most out of both Suno and your prompt. And the result is better music is being created here than what you can create on Suno. Suno songs sounds very similiar to Tunees, but since Suno only allow 32 seconds long cover songs instead of say 3 minutes like Tunee, do I consider their product as inferior and barely useful. Tunees is clearly so much better.
However lately have many changes been done at Suno. The company has been teaming up with Warner Music Group, and it have made changes to its app and licences to other companies that wanna borrow it. And that creates problems for Tunees when it relies on a company that has become a competitor.
So therefore do I not think that the situation would change anytime soon. Unless Tunees either can come to an agreement with Suno soon. Or if Tunees somewhere finds a new AI music creator as good as Suno to use instead, which I guess is unlikely to happen anytime soon.
It seems like the music generator is holding Tunees hostage. Just like it is difficult for Sweden to sell Gripen fighter jets when it has to rely on an American made engine and relying on the goodwill of a foreign entity that can veto any move the company makes. And the incentives to mess with a competitor is probably also there if you compete for the same pool of customers.