I similarly only play Career Mode so the Switch version is absolutely perfect for me.
That said, if you've now played and like the PS4 version, the Switch version will likely feel a little different. The Switch version is still based on the Ignite engine I believe which was used for FIFA 14 -16, whereas obviously 17 and 18 on other consoles now use the Frostbite engine. As someone who really didn't like FIFA 17 and so just kept playing 16 for an extra year, I would say that the Switch version does feel like an upgraded version of FIFA 16.
Whereabouts are you based? I only ask as FIFA 18 is currently as low as £22.99 on Amazon which is a bit of a steal. You could give it a go and then probably just sell it for your money back or more on eBay or something?