Why different fonts on different devices?

That’s because it is a different font.

You’re not going mad, but if your accuracy depends on text using the exact same font then you will likely have tons of issues down the road with recognition. Especially if you ever encounter fonts that emulate a handwritten style or actually encounter handwritten kanji because they aren’t going to look 100% like the fonts in your screenshots. I would suggest you use something like this to eliminate this crutch of needing one specific font to be accurate: