There's no easy answer to this. A while ago I did some research because I really wanted to do The Right Thing™ when formatting an SDXC for the Jolla phone.

From what I understood then (and what I still remember), it's pretty easy to make mistakes without ever noticing (except that the card will be slower and wear out sooner, which you will not know because you didn't test before/after.) One aspect is that file systems in general should keep write operations to a minimum. Journalling file systems have an overhead in this regard, so they might not be the ideal choice. The nice thing about FAT and its children is that they are so unsophisticated, making them a good choice. This is a general (and probably: too) general answer, though. You'd need to compare pros and cons of each file system on flash memory to get a valid answer. (And I, of course, only compared the choices natively available in the Jolla phone's kernel. In this comparison, FAT32 seemed to be the only reasonable choice.)

The other aspect is that when you found a file system that you think is good enough, you'll need some information about the hardware of the SDXC card to keep the logical blocks of the file system and the physical entities of the card in alignment. Otherwise, you'll end up re-writing two 8GB (or larger) blocks when you'd only need to change a few kB that are the file systems smallest unit. Obtaining this information about the hardware is tricky. In theory, you should be able to read it from /sys/block/<devicename>/device/preferred_erase_size and fromcurrently set exFAT parameters. In practice, the value in /sys is often either missing or incorrectly set to 4GB. There are tools that help you detect the right values, but they need human expertise to interpret their output.

So the bottom line is:
When you re-format your card, even to exFAT, chances are very, very high that it doesn't work as well afterwards as it did with the pre-formatted file system. What's worse is that there's no tool that will tell you: "Ooops, something went wrong, block alignment isn't perfect on this card." You'll just keep using a card that is slower than what you paid for and will wear out sooner. So I'd prefer not having to do all this again.