An ultra wide is a good choice too, I also have one but use it for my "desk" games, the triples are on a fixed race sim setup.
Prob with ultrawide 21:9 and more so, the even larger ones ( 32:9
forget the aspect ratio) is they stretch at the edges quite a lot.
Proper triple support (as seen in almost all race sims) do multi-projection (or whatever its called) so no stretching at all and gives you more peripheral too.
One bezel is usually covered by the A pillar of the car, the other isn't really that distracting.
This is a really bad picture, I used my phones panoramic mode to try and grab it, because its so wide, so its not 100% but gives you an idea, these are at 50 degree angles to each other, not flat.:
When sat in front of it, everything appears correct and pretty accurate. It's also much more comfortable (and clearer) than VR for long sessions.
This is ultrawide, you can't really tell just from the image here but the left door mirror is stretched and you see considerable less with relative fov settings (at correct world scale)
When you pass a car, you see its size change.. not drastically mind you, 21:9 is actually pretty good for sim racing, imo. 32:9 is horrid, in my opinion.
But, triples are not always supported.. i.e Dirt Rally 2 doesn't, so you just get stretched peripheral anyway.
3 x ultrawides anyone

?
and sorry for the few edits, took a while to find the pics