I agonize over every purchase. I got the RF 24-105 f4-7.1 with the R6 body just to have an RF lens to shoot with, (no canon adapters available) and because it was the ONLY configuration available in stock anywhere to buy at the time. But honestly, I rarely use it now.
When the RF 50 1.8 came out, I bought it just because it was cheap and a handy knock-around lens to have. I can throw it in a small case and take it in my motorcycle saddlebag.
For weeks, I agonized over something to do portraits with. One that would pay for itself. I LOVE all the BIF photos, but I don't bird. So, I took the plunge and bought the RF 85 f1.2. HOLY COW, what a beast of a lens. I honestly wasn't prepared, and I'm still learning how far I can push it. For portraiture, it'll be my go-to, hands down.
I can't wait to try out the 28-70. I've been wanting a zoom in the RF glass since last fall when I got the R6. I'll probably eventually get the RF 70-200, but I have an old EF and an adapter to use for now if I need it.