How likely is it to reach Diamond?

@DavidW74I never said anything about camping WITH randoms. You do it solo if/after they die. Don't die with them.
I did it all the way through gold and until plat2, then I got bored and just finished up with a couple of randoms from discord (same style of course, just a lot more wins with 3 ppl alive in the end). I could have done it all the way to diamond4 alone too - would have taken a couple more days, but not that much more.
You don't need to be good at shooting (e.g., my highest kill count is only 16, and even that one was not in ranked). You just need to be decent at predicting enemy movement (jump for end of plane path zones, watch where EVERYONE is landing and make mental notes of how they will be moving when you see the ring), find the spots of least concentration and have at least a mild idea of where the final circle is going to be. And of course have a lot of patience (but that one should be found in abundance, if you like BR's XD). I fight when I think I have the advantage, but when I'm solo that's quite rarely the case.

Also, there's no best way of playing the zones - sometimes it's best to stay outside and keep medding until 3rd or even 4th zone (always carry at least 2 stacks of bandages and every single first aid you can find - you can drop em when you go back into the zone), sometimes it's best to find a cozy spot near the endzone as early as 1st zone.
When we were doing it with the whole team, we could be a bit more aggressive, but the ultra passive playstyle is still the most superior to rank up in season1 (if you can't accept that not dying is the goal #1, then maybe that could be the reason why you feel stuck).
When I was doing it solo (not counting times when my random team did not die), I'd say I got top10 in every game, top5 in at least half and most of those top5's turned to top3. Wins solo are pretty rare, so the general goal is to try to get to top3 and then go rambo style 3rd party on the last 2 (try to determine which team is the favorite to win the duel and kill them first).

I'm not suggesting to just ditch the randoms at the start and pretend they don't even exist. Try to play with them, but the moment you risk dying - you just leave them and go away. Heroic banner recovers under fire from 3 enemies may be fun and all, but they're almost never successful (sometimes the enemies don't camp the boxes though, so recovery may not be out of the question - just make sure it's safe). That's the most optimal way to play with randoms in platinum (the main culprit of this is the inability to derank below plat4 - there are WAY too many ppl who are at bottom and don't even care about winning).
P.S. When I was playing with randoms, I always tried to persuade them to play conservatively, but usually I was just called various names and then THEY intenionally split away from me and chose the most concentrated zone XD. So I'm not sure if talking is an option with randoms - play along if it's good, but just leave em be if it's not. Agressive playstyle is very hard to pull off (without losing points in the long run), since it's extremely inefficient (so you have to be MUCH better than average opponents to do that); and you should be rightfully sceptical when plat4's try to do it...

As for console - I've no idea - never even had one of those.

P.P.S. From my experience, games don't get tougher as you rank up from plat4 to plat1, diamonds are not put in plat games. So if you could get plat2, you can get diamond too, as you're still playing the same quality games. As soon as you get to diamond though, the games change completely.

I do know though that some smaller servers don't have enough players and plat games do start to get mixed even with predators, so if you're experiencing that - try a different server and maybe play at a time when there are more ppl online. Playing vs predators does not give you more points in plat, so there's no reason to ever do it - find a server that offers plat-only games.

Anyway, GL in your further climb. Don't stop when you're more than halfway there!