There’s zero MS in the stack on anything with SYNC4 and newer. Your salesperson is wrong. Even development is largely done on Ubuntu. SYNC 4 has two front ends, one’s Qt which has some Panasonic outsourcing baggage, the newer one is web based. The latter is what’s in the Mach-e. Since about 2017 all of this has moved in house. Ford hired the whole BlackBerry mobile R&D org in late 2016 - people, offices and everything. It’s had an honest-to-god software org since then.
Your Flex probably had the older SYNC iteration that was MS developed. BTW I’m not sure if it was Windows based or whether it was QNX with MS devs creating the software stack on top of it.
I was pretty surprised to learn that Interac e-transfer or equivalent isn’t commonplace everywhere.