Its good to question as I think there is always more to any claims made by various docos, including Cowspiracy. Very hard to fully isolate and quantify the impact of meat production in one definative way. I would say it is also very dependant on the farming practice and ecosystem of specific regions.
I found some well presented data and discussions on this as a starting point. (It is probably reputable as it appears to be funded by random public donation. Although after snooping around, I saw Bill Gates fund was a major contributor, and he has huge interest in plant based meat.)
That data does touch on some specific regions and practices and splits beef into dedicated herds and dairy herds (which have much lower impact), but I think there is still a lot missing.
There are also pro-meat movies made with counter claims (this one is mainly from a guy who appears to be employed by meat companies and has some flaws), giving starting points for questioning.
I imagine it is very nuanced as for example, in the pro-meat video I linked above, the counter claim made that ruminants just graze grassland that would otherwise be wasted is true in some countries like New Zealand pastures, but false in others where rainforests are cleared for grazing. And in many places all of the water that is consumed by ruminants is just rain that would fall there anyway, but in other places they will be diverting from fresh water sources. Likewise in New Zealand all the cows eat grass that grows there anyway, but in USA, most of the beef is grain fed and those grain need additional resources to grow. Mind you, grass fed beef has its own issues like poluted waterways and more methane.
Likewise health claims such as beef being "as bad as smoking" may only apply to grain fed beef which has 10x the omega 6 ratio of grass fed beef, therefore people in countries which only have grass fed beef may be much safer from meat enduced early death.