Okay, it's been a little while now and it's time to turn some of the previous "observations" into criticisms. They fall pretty much into two categories.
#1: Live teammates
I know I said I didn't care if there was somebody on the team who went around vacuuming up all the enemies. And I kinda don't. If it's one match. Maybe two. Out of a session. But it's becoming pretty much all of them now. And it's the same criticism I had of Halo Guardians Firefight mode. It too was team-based, only the teams were larger so the effect was immediately recognizable. A handful of the most aggressive and mechanically gifted players run around cleaning up the field. It isn't that I'm incapable of keeping up, or of eliminating whole squads of bots. It's that I no longer have to. If someone else is doing it for me then one of two things happens. Either I'm irrelevant, don't need to do anything at all in order to win, and get bored. Or I have to allow the game to turn into a race. A race against the clock, against the speed of my squad mates, a race to the next survey beacon and to the next cluster of red dots. Faster. Faster. Faster. Which is anathema to someone who makes the entire battle royale experience all about pacing. The slower the better.
In team-based PvE your teammates always become your de facto competitors. Sometimes sooner. Sometimes later. But always inevitable.
The fix here is like I said before: a lobby option between a) no fill, b) bot teammates, and c) live teammates.
#2: Bot behavior
It doesn't take long to figure out how to beat them because their behavior is extremely predictable. If you get too close to them on the ground then you'd better have an aimbot because they do, especially if more than one of them can get a shot on you at the same time. But if you have the ability to rapidly put distance between you, especially vertical distance, then they mostly just stand there and take your mid-range fire until they go down. They move sometimes, after a shot or two, but even then don't seem to distinguish between cover and open ground. Which gives any mobility legend a quick hack for dispatching squads with no real danger. And when you can do that with virtually every single engagement then you're not forced to find other tactics, explore other weapons, or rely on teammates for anything. All of which means that bot royale is not very valuable as a learning tool, or even a practice tool, as I assume it was meant to be.
The fix here is variable difficulty from bot to bot, including motion and evasion behaviors, but also aim. Not every bot needs a close-range aimbot. Real players in trios may all have them, but I don't find that very plausible which is why I don't play the main game much any more. Bots certainly don't all need it. Some, sure. All, no. They also need to not all be Fuse, Bloodhound, Lifeline, and Wraith. And if they are going to be drawn from a small pool of legends then they need to be "taught" how to use their tacticals and ultimates. And they need to carry guns other than the nemesis. And also consider the possibility of scaling their difficulty as the match progresses to keep the experience more in line with the way it works in trios and ranked.