I think you need to start trying to think about this issue as an older person would. If you truly want to have a capability that a specialty tool offers, then you need to either own that tool, borrow it, or rent it, otherwise you'll need to skip or miss opportunities. You're looking at the lens as money spent, not as opportunities is allows you to capture properly. It's a lot like many other tools: if you drink wine in corked bottles a few times a year, you need a corkscrew, even though you do not use one every single day, or even every week. Same thing with a pizza stone...you probably do not use one every day. Same with a tire jack...you probably will only have one flat tire per year--but your likely carry the jack and spare tire in the car 24/7. Why not get rid of both the spare tire and the jack?
I guess what I'm saying is this: you need a mental re-set to get rid of the worries you're having. But then again, you stated that you're not even sure you want a Nikon anyhow, so...obviously you've got cognitive issues troubling you as to what your idealized photo outfit consists of...maybe you would be happier with something else, like the Fuji, for smaller camera size, more portability, and a different "look" to your camera, something more sporty, less camera-nut-like?
I've seen this type of worry among many younger people, the tendency to look at an expensive lens as "money sitting around", instead of "capability just waiting to be exploited". It's a mindset. The better way to look at lenses is as sunk costs....buy it once, KEEP IT for your lifetime. Or, if it's something you will use occasionally, buy a USED one, so you're not always having a form of buyer's remorse on a $700 lens purchase. Or, buy a much less-expensive choice, like say a used Tokina 100/2.8 AT-X macro, so you have a lot,lot less cash invested in having that capability. SOmehow, you need to either reconcile the competing thoughts of money sitting around and capability just waiting to be exploited. Or, perhaps you really don't even want or need a macro lens or the capability to do macro work, and you really want something else.