Our Ford in-dash updates for our Fusion (SD based Sync 2) are also expensive from Ford itself, but often within a few weeks they show up on Amazon/eBay for more reasonable costs. No issues at all with compatibility.
Our newer Explorer (Sync 3), however, looks to be a bit more problematic. The updates only come on an encrypted USB stick or download direct from Ford; but our first one was free (2017 data -> 2019 data). Not so sure what will happen down the road, but I suspect they'll be expensive. There are hacks available, but I'll continue to be reluctant to use them in the future as there's a lot of "features" that run through the infotainment system and I certainly don't want to brick it and loose warranty coverage!!
We can use CarPlay as well so that will be an option if we need newer information.
In general, I much prefer the larger in-dash Ford display vs CarPlay. Frankly, I don't often see many real changes in the updates although I'm sure they are present in some areas.
Ken