I won't give advise, but I'll relate my personal experiences regarding a handful of different sportbikes:
The suspension is there to be your 'instant on personal coconut telegraph.' The main participants in this dialogue are (in no particular order):
1) Your brain, your butt, your hands, your feet, your knees/thighs, and your eyes. Any of them at any given second of any given minute can feed your brain significant information.
2) The tires (& wheels), these lovely black rubber/silica doughnuts dance on a ≈ 2.5" X 2" interface between you, the rider and the tarmac. The information they supply is ever changing by mere fractions of a second. Many factors affect the ultimate flow of data.
3) The suspension & chassis I'm gonna lump together, only for the sake of simplicity. Yes, they are separate, yet joined entities. Stating the relative obvious fact that in the vast majority of cases one is not going to be altering the chassis, but it is a very real possibility, none the less.
Most people I believe, place too much emphasis on twiddling the fork. Yes there are gains to be made there. Likewise most people neglect the rear end of the bike. Why? because it's not glamourous. Few see the bling when tuning forks and shocks. Personally, I think getting the shock dialed in is a 'must do.' Why? The shock affects every in./mm from the head stock back - that's most of the bike; it's also where the rider is. The front suspension takes its cues from the rear suspension/tire/spockets, etc.
I have learned the hard way where to invest mods on a sportbike, that doesn't mean I haven't performed purely adornment mods early on it the mod(s) phase. I certainly have. And some are done early in the relationship to accommodate my aging body, as well as my vanity. But no one makes suspension changes for their vanity - unless it's to keep their pretty face & the rest of their body (& the bike's) pristine.
On a street bike that maybe sees a little track time with a track day/school, but is otherwise used for pleasure/sport/transportation, etc., no non-sport bike rider will ever noticed you dumped nearly $12,000 on a set of Íhlins FGR300 (I used the most extreme for dramatic affect), or a cool eleven hundred dollars for a nice, but not top the line, but still used by factory/privateer racers, Íhlins TTX RT shock. But I think a mid-tier shock by K-Tech, Nitron, Íhlins, or Penske is a wise move for an upper 'B Group/A Group' rider. If you don't know that means leave your bike stock and enroll in a track day school ASAP. Also save your money on rebuilding your stock shock. They are not as rebuildable as aftermarket - no not even as stop gap. I've gone down that rabbit hole.
I also found that having my OEM forks re-built with new internals is a savvy move. This will get you to the 80-90+ percentile. But this would be a little on the back burner, because there are other things to sort out prior. Or another way I look at is, this is a nice to have, and not a need to have... until your riding abilities come up quite a bit.
A track only bike, also benefits from a mid-upper tier shock. I still think for a lot of 'A Group' riders can get by with new fork internals. Or at least until one becomes a contract rider for one of the major suspension manufacturers. What I found made a noticeable difference with bike transitions from little chicane wiggles to full left-full right; decreasing radii, off camber to off/on camber transitions are... wait for it... hold your breath... aftermarket wheels.
Now, this is a big-ticket item that really is over kill on the street, but on a track, at speed, they make quite a worthy asset to have. My experience was like I was on a completely different bike, so much so that I had to re-programme my brain to ride quite a bit deeper into the turn, otherwise I was turning in way too early. Sometimes clipping the inside of the turn that I was/and did come off the track a few times and on to the kerbing/rumble strip. But they are damn nice to have, and oh-so bling! Shwing! Beautiful.
Do I have aftermarket wheels on my ZX-6R? No! It's a street, mostly bike; me & my body are just to old. It sees the occasional track days, but that's it. I'd probably spend similar money either on track days, or on taking my 636 to the Rockies for two weeks, or ride down the California Coast, and back up through the Sierra Nevada/Cascade Ranges. (Though not right now with the tragic fires.)