I only like arcade racers and I love Forza Horizon. The online components of entering races with other players you can totally ignore. The open world events (Forzathon, if it'll still be called that) are pretty fun and collaborative rather than competitive.
If you like having a wide variety of cars to drive, a bunch of different race types (road, street, dirt and cross country racing) and great looking scenery then it'll definitely appeal to you IMO. There's also open world stuff like danger signs (stunt jumps), drift zones and speed traps/zones which I think are pretty fun and a nice break from races.
It plays great with a controller, all you need is accelerate/brake/turn/handbrake and you can complete most content (maybe not drift zones).
FYI if it's like FH4/5 it defaults to online but there's no need to turn it off as other players can't get in your way and there's not that many people on each map anyway.

Shhh, don't tell them that buying indie games helps indie devs even more!