Having four accounts is really quite exceptional. I'm experiencing some burnout with just one and 1200 hours played. It's a testament to how good the gameplay and interface are that it's still so engaging.
It might sound counter-intuitive, but playing on 4 accounts has greatly improved my enjoyment of the game. On my main account, it's too easy to get platinum, and it makes it a chore for me. I have plenty of cars and credits, I have full gold parts sets, I basically just buy the cars, do each event once or twice, and I've got platinum, there's no challenge and it's completely boring as a result. I got the accounts when the game was on sale, and my original plan was to do the summit each week with green parts on one account, blue on another, and pink on another. But it quickly became clear to me that the parts aren't a problem at all, and it's pointless doing the green/blue/pink parts accounts as no new player needs to do that.
The first thing I had to "grind" on the new accounts was 10 playlists to unlock fast travel. Now, that might sound like a chore, but what happened was that each time I did a playlist on a new account, I was better at it, and did faster times. That actually made it massively more fun for me than doing them for the first time on the main account. When you just do them once, and all you have to do is complete them, it's a chore. When you do them on other accounts and are looking to beat the times you did on the first account, it becomes competitive and more fun.
The same happens each week with the summit. I do the events on the main account and it's all too easy and no fun. But then on the other accounts, I have no money, don't have perfect parts, don't have loads of legend points, so I have to actually put some thought into the most efficient way to get platinum. And then I do an event with a less good car and worse parts and beat my time from the main account, just because I've become a bit better at the event. I move onto the next account and go even faster. This starts to make it fun.
On the subject of the Nevera Time Attack Edition, I'm not sure the car is going to be good. The summit event with it loaned is the first Donk event from Donk & Lowrider. I've tried that event in custom mode with some other cars, using a bucks set to make it a fair comparison, and the Nevera Time Attack seems a bit slow. It depends how much it can be improved with tyres, body parts and pro settings, but in standard form it seems a bit off the pace to me.