Either we’ll get a shot or montage of the council of Kangs getting prune. Or they’ll just prune them off screen, or they’ll replace Kang with Renslayer lol. Then they’ll start planting Doom easter eggs until his big reveal. Cap4 will probably name drop Latveria or show its flag. Doombots and important Latveria residents then will begin to appearances in future movies. Doom will probably get his big reveal in F4.
Naw breh.
Doom isn't putting the casual viewer back in seats.
Marvel are at a low point and there is now a lack of interest. They need a risk aversive sell.
The easiest and safest villain to replace Kang with is none other than... THANOS.
The audience is already familiar with the character and the character was well received. Thanos returning after 6-7 years would generate interest.