Most guitar pedals are 9V DC but not all.

Some are 12v. Some will take 18v. I have an oddball that takes 9V AC. Some are 9V DC but flip the positive and negative. It can be a mess too.

The product you link to has outlets for 9V, 12V and 18V.

If you stuck to one PC manufacturer, I’d imagine you could have your wish. Dell laptops were the same 19V and same DC pin for years and years.

I thought USB-C PD would save us but it has a few pitfalls, apparently.