Matchmaking is better at lower SR, it's already a lot better at low SR.S just above SR.A. With my qualifying time today at Nurb 24h, SR at 85 put me in 2nd place while SR at 99 puts me at 14th place. Most of my wins come from getting demoted in SR first, which will happen naturally when you stop backing down. People will still run into you, yet the system rewards you for getting hit...
Winning at max SR is very hard as you will get matched with top 10 drivers or any of the faster drivers that can't find a full room at their level. It's easy to reach and maintain max SR when you get placed on pole in a room full of slower players, hence when you get to max SR you get used as grid filler by the matchmaking system.
When you're DR.B nothing wrong with being SR.B as well. That removes most of the DR.A and DR.S players from 'invading' the DR.B matches.
Don't be afraid to get hit, anticipate it so you don't lose control, and a red ranking at the end only puts you towards better matchmaking grounds. Just don't go below SR.B Never been there yet have heard stories