Well, I'm also looking at it from the perspective that we may just plan to upgrade our computers a bit more frequently and trade the old ones in to Apple. At least while we're both working and making a decent income. When thinking that way, another comment deeddawg made applies: Apple only gives you a small fraction of the extra money you paid for those upgrades.That's ok for now, but consider OS updates, applications in a few years etc and future and longevity. Look at 2014 MBA with 4GB to 8GB and their ability to smoothly run Catalina. RAM is better upgrade to CPU in most cases. Just MHO. Storage is moot point if you are OK with plugging in another device. I've moved now to M2 SSD for external use and this is fine, quick and quite cheap if you need to shuffle things around to be on the move.
But, yes, if I was thinking of this as a long-term purchase, I'd probably go ahead and upgrade both the RAM and the storage space.