I know this is about a month after you posted it, but I only just saw it at the weekend and decided to give it a shot myself. I've never tried Beam's rally mode so it was a bit of a thrown-in-the-deep-end experience, but after a couple of hours I got a star!

I was much less tightly controlled than you and only got a 4:16, so it'd take a fair bit of practice to catch up, but it was good fun. I always find Beam's relative lack of lateral grip a bit frustrating to drive with, but on gravel that suddenly becomes totally fine. I was throwing the car a lot more sideways than you, which seems to work for me... at least some of the time, but I'll need to clean it up to improve my time. It's possible that it's at least partly a consequence of me driving with a gamepad instead of a wheel & pedals setup though. I've got less fine control, but I can also go from full steering one way to the other basically instantly

I was able to go from the point at 2:23 in your video all the way to 2:40 at full throttle, so that might shave a bit off your time. I really need to figure out those narrow sections at 3:27 and 4:46 though, besides general smoothness I'm pretty sure that those are where I'm losing the most time