One of the most mediocre DLCs ever released for a Horizon title. Functionally it works and I have no doubt some developers put in lots of time to get it polished but it really fails to deliver on rallying in so many ways. For starters, I have no issue with the presence of the helicopter, but it flies so low that it's constantly throwing up dust in front of you, affecting visibility. If I squint, maybe 1/3 of the races resembles actual rallying. A solid 1/3 of the routes are just asphalt roads with pace notes. The pace notes also fail to use the number rating for the corners making it a complete crapshoot to try to drive purely with pacenotes and immerse yourself in the feeling of rallying. The map is tiny and just feels like they cut out a piece of the main map and remixed it. There isn't really any track variety such as forested trails or rallying through tight favelas.
Also for some reason the physics of the whole map is slightly different from the main game. The easiest way to see it for yourself is to take your favourite drift vehicle into the asphalt drift zones on this map. Or to use your favourite CC vehicle and just try running off road to rack up a skill streak. Nothing handles the way you expect it to and I don't know why they felt the need to change it.
To be honest I think it's mainly good for the extra 2 seasonal missions you get once you complete the DLC. Do yourself a favor and get it on a sale. You may get 4-5 hours of fun out of it, more if you aren't actually into rally and just want to play more normal FH5 with some rally set dressing.