I have two 27" monitors (1920x1080 and a 2560x1440) on the edges, with a 28" 4K monitor in the middle.
Basically, the middle one is at a comfortable distance, with one coming off each side angled to be kind of an arc in front of me. It does take up a fair bit of the desk, but I have all my external drives, recording paraphernalia, and some other misc stuff behind the monitors, with my KRKs (speakers) to the sides of the main monitor (kind of peeking through the gap between main and side monitors).
I find that it works quite well, and I can read everything (apart from a few programs that don’t scale their fonts on the 4K monitor), AND I have lots of space to work with.
It really depends on what is comfortable for you. Even having two monitors makes a huge difference (IMHO).
Once I got used to multiple monitors, I find it REALLY hard to go back.
And as jwatte said, you can just pick up cheap ones for the flanking monitor(s), it’s really about being able to have things isolated so they don’t get in the way of other things.
BTW, I didn’t just buy three monitors. Each of the secondary ones are my older monitors. i.e the 4K is my current primary, the 1440 was my main before that, and the other the main before that, etc, etc.
You can always do something similar, get a cheap one to see what you think, and if you like it (or later when you are up for it) you can buy a bigger, more expensive one and then either retire the cheap one, or use it as a third.
IMHO it’s definitely worth giving a shot though.