Luka Doncic's Ex-Fiancée Wants $50M and More Custody

Luka Doncic's ex-fiancée Anamaria Goltes said she wanted to settle their issues amicably ... but TMZ Sports has learned she's taken their fight to Slovenia -- and as far as she's concerned, the cost of settlement is $50 MILLION!

Sources with direct knowledge tell TMZ ... Anamaria has filed a new claim in Slovenia ... and she is seeking $40 million for herself ... we assume the remaining $10 million is for their two daughters. Luka has said he'd do anything for his kids, so $10 mil may be realistic for them, but the $40 mil is a whole other story.

We're also told she wants to strip Luka of some of his custody rights. Currently, he has the kids at least 2 days a week, and she wants to reduce it to one day a week.

As we reported, Anamaria filed docs in Los Angeles this week asking to withdraw her child support petition ... saying she wanted to resolve the matter "amicably and by a mutual agreement" in the best interests of their children. But apparently, that will come at a steep price.

Luka and Anamaria share 2-year-old Gabriela and 7-month-old Olivia ... and were together for a decade before ending their engagement earlier this year.

Luka previously argued California was the wrong place for the fight because the girls live in Slovenia, and said he'd already initiated proceedings there addressing custody and support. Frankly, that seems like a solid argument, and Anamaria may have dismissed the California case because it was a loser.

The Lakers superstar is currently in Slovenia to be closer to his daughters ... after revealing in May he'd skip playing for his national team this summer while pursuing joint custody.