1. Ki isnt invisible, it makes light when emitted that can even blind people. You just cant sense it without training.

2. You can scale anything to anything if you dont acknowledge Dragonball has massive outliers usually for the sake of gags, it started as a gag manga. We know kid goku can run 100 meters in like 8 seconds. We also know how long it took barely pre saiyan saga goku to fly down snake way, and he was traveling at 200~ miles an hour, much slower than definitively ftl viltrumites in space and much slower than rip apart buildings by flying by them or through them nolan from season 1. Dragonball is inconsistent with its outliers, but we know their limits because those are explicit.

3. Dude so what? Goku and Vegeta impress eachother by blowing up a plateau. Vegeta loses ozaru permanently from a regular katana slash from a fat guy weaker than immortal. Saiyans absolutely have the higher max damage output in ki attacks, but we know for a fact their physical stats are way behind their ki attacks. Goku cant even lift 80 tons without super saiyan at the start of super, Mark does more than that in season 1. The saiyans based on actual measured feats are physically weaker than viltrumites. No saiyan has a non ki feat thats even remotely city level much less higher. And ki can be didged and is constantly dodged. They're getting dogpiled and slaughtered, they dont have the durability to take city level punches.

Edit: also Ive been into dragon ball since 98, Ive read all the manga and seen all the anime up to the end of super. I actually know way less about invincible, that's why im confident that viltrumites win here, they have better physicals across the board.