Hitler was notoriously distrustful of Serbian nationalists so I don't think it's going to be a Serbian wank necessarily. I think a rump Yugoslavia is more likely after Italy, Bulgaria, and Hungary get their choice territories (though Hungary isn't getting much more than they got in OTL due to conflicts with Romania.) Remember the guiding principle of the Third Reich's policy in the Balkans was to keep things quiet and maintain the pre-war status quo that saw Germany dominate the region's economies. OTL's Greek campaign and the March coup nixed this idea, but I would argue that German policies following that period show their inclination towards preserving regional stability. Without the Ustacha having Italian support I think they'll turn to what was a fairly successful pre-war model with some alterations.
In such a scenario the Croats probably retain the degree of autonomy they received in 1939 in OTL, but much of the extreme Ustacha violence could be averted. Tito's partisans are weaker in TTL due to less persecution of Serbs in Croatia. The Chetniks are likewise stronger but this probably leads to more German offensives against them (Even into February 1944 the Germans saw the Chetniks as their primary threat in Yugoslavia.) Nedich comes out as the real victor in this scenario, without the refugee crisis in Croatia, he only has to deal with the smaller one in Kosovo and the additional pressure on the Chetniks likely drives more bands into his orbit. Furthermore, when the Italians surrender he'll be able to "reclaim" much of their territory. Yugoslavia probably doesn't tie down as many German troops as OTL, but I don't think this has a major effect on the course of the war in general.
The real interesting situation is going to arise in the post-war period and it will be very much determined by just how weak the Partisans are in TTL. Tito had a number of close calls in OTL, does the partisan's weaker position in TTL mean that he gets killed? A weaker partisan position is going to mean that Yugoslavia is liberated almost entirely by the Red Army. Furthermore, the persistence of the Yugoslav state in TTL likely means that it is completely discredited as an idea, especially without a strong vision of a socialist Yugoslav Federation waiting in the wings. It's often forgotten that in OTL tens of thousands of Serbian nationalists fought with the Wehrmacht right up until 1945, this number is even higher in OTL and likely serves to further discredit the idea of Yugoslavia. Stalin is going to be left occupying Yugoslavia and may not have the option of handing it off to Tito in TTL. This could go one of two ways, either Stalin agrees to Finlandize the region and withdraw, or he reluctantly expands the USSR's defensive perimeter. If he opts for the latter, it could be disastrous if he decides to use population exchanges to carve out new ethnic nations out of Yugoslavia.
A weaker partisan movement also has impacts elsewhere. Without Yugoslav support, the Albanian communist party might not take off. If it does Hoxha and Xoxe are likely nowhere near the top of the organization. There's a good chance in TTL that the Albanian resistance takes on more of a nationalist character and the country aligns itself with the West after the war. The Greek civil war is also likely much shorter as well without Tito and Hoxha.