The only clues (at least as far as I can remember) we've gotten about where either game is set are:
MNF:
It was part of the Roman Empire in ~CE 600 (Becca in the roman place she takes you during the second vacation), it's not Germany (idle dialogue during first vacation), it's not Spain (multiple explicit mentions of Spain as being far away (like Fiona offering to fly the MC there)) and it's not Italy (Likely, MC says "While my classmates were off exploring Italy).
It's possible to reach other countries by rail (First vacation, on the train, "don't fall asleep we might end up in a different country" or words to that effect).
Everyone speaks English there (Sun's dialogue).
It's coastal and at worst temperate (presence of palm trees, general climate).
MNM:
References between the games mention an architect in a "different country", so we know it's not in the same country as MNF.
My best guess is that MNF is set in an alternate history version of earth where there was an American (or maybe British) occupation zone in Italy that gained independence somepoint after WW2, kept the language and a distinct identity to Italy proper, and that game is set there.
More interesting to me at least is when the two games are set relative to each other. It kind of seems like they're both set in each other's futures, with dialogue in MNM talking about Maddie already having her fitness channel being set up, and dialogue in MNF implying that the MNM MC's amnesia is a thing that is in the past.
As for technology... idk, maybe everyone in MNM just have really old phones and MNM:TB is set shortly after the invention of smartphones in universe... it doesn't really matter.