My first DSLR was a Nikon and one of the first lenses I purchased for it was the Nikkor 70-300mm. I thought I was in photographic heaven but as I got older and wiser that changed - it is a nice zoom range but the image quality was a diffferent matter. Fast forward a few decades and I was looking for a similar lens for the Fuji X-T5 and after reading several reviews on the Fujinon 70-300 and talking to "Fuji friends" decided to risk it.
Returning to my Nikon days, my all-time favourite lens was (and still is) the Nikkor 300mm PF - stunning IQ and so very versatile, anything from birds in flight to insect close ups, so the first serious outing with the Fuji was some close-ups of seeding dandelions.