Dabura would be a very difficult opponent for Galu and Vegeta to deal with. On top of being stronger than them in this scenario, he seems to be a very skilled fighter from what we saw in his fight with Gohan and his magic would make him a deadly threat regardless of the opponent if used correctly, the potential combo of his magic Zanzoken with his unreadable Ki (at least in the manga) followed by a stone spit being absolutely broken. As he's not limited in stamina as Freeza was and Galu would let his guard down (
2 ) it's probable that Dabura would be capable of killing both the Saiyans even if they decide to fight together so long as he plays things smart.
Taking into account material outside of the manga such as the anime filler of DBZ Kakarot, I'd say Dabura wouldn't aim to take the two Saiyans' lives and instead just wish to prove his superiority in a fair fight, coupled by Beerus' presence making him uneasy. Once he's done so, he would decide to return to the Makai, though is given an offer by Whis to become Beerus' successor to which Dabura accepts. Thus, he joins Goku and Vegeta in training from time to time when not busy governing the Makai. He takes Boo's place in the U6 tournament, being the one to defeat Hit instead of Monaka. I'll say he doesn't participate in the battle against Zamasu due to limited space in the time machine and him considering it a better decision to use his knowledge to aid Shin and Beerus with the Zamasu mystery, though he would hear of the domino effect caused by his future counterpart and feel some guilt in his past personality and offer some training for Trunks to help him learn some Makai magic to aid him, perhaps boosting his healing ability. For the ToP, Dabura is obviously chosen. Perhaps some of his strongest subordinates would replace the Earthlings, though that seems a bit too speculative, so I'll say the only difference is him replacing Freeza. His stone spit would be difficult to utilise when pushing his opponents off without breaking the no killing rule, but his other magical abilities such as his flame breath and weapon materialisation (along with low-level regeneration and teleportation if including video game techniques for his powered up arsenal) make his already great power a valuable asset. Dabura would be smart enough to stay back with Gohan and co. to play this fight strategically and easily stop Frost when and if he attempted to take out Kuririn. With his training with Whis, he'd have caught up to Goku and Vegeta, allowing him to last as long as Freeza did and his magic would allow Goku and #17 to take down Jiren with less difficulty.
Due to there being no Freeza or Freeza Force left (as Sorbet's group would likely have been killed by Dabura's men when searching for the DBs), DBS Broly never happens which changes nothing, showing how much of an inconsequential time waster that really was
. For the Moro Arc, Dabura would only get involved after Whis' meeting with Merus in which how this related to the Kaioshin would make it an otherworldly matter the Makai could not ignore. That said, Dabura comes to assist the Dragon Team when Moro arrives on Earth. Seeing Goku achieve a power thought only usable by the Gods as well as how much Gohan and Vegeta managed to progress within the ToP would've motivated Dabura to train harder than ever. I'd say he'd have far surpassed Gohan by this point and be capable of either defeating Saganbo alone or overcoming his beyond limits power up with the help of everyone else, though be outmatched by Moro. Gohan's Ki not rapidly decreasing would mean Goku gets there immediately to face him, though how that goes we'll have to see. I'd say Gohan would go to aid the Earthlings in their battles, though Kuririn would likely have been killed by the fused female fighters due to the delay by the time he got there.
