I know there are monospaced fonts that have the same width per character, but they don't solve my problem.
I'm looking for a pair (or more) of fonts that have common glyph sizes.
I expect that if I write any string using font A with size x, it will have the same width as if I write it using font B with same size.
Do such fonts exist? Do you know any?
In Microsoft Windows, the Bahnschrift variable font is "duplexed", meaning that the different weights have the same widths.
https://learn.microsoft.com/en-us/typography/font-list/bahnschrift