Can't really speak to round count or cycle life in the Staccato C's mags, but I'd be surprised if they weren't excellent. You can also get new mag springs from a couple of places though.
The number of spare mags to get depends a little on your mindset, what you want to do with the gun, and expected future availability of mags. For me personally, it's a lot, if for no other reason than it makes your time at the range much more efficient, and it gives you the ability to pull a bad mag without going short on mags. It also buffers against things like mag bans and supply chain issues.
In general though, for a safe queen, 3-5 is fine. If this is CCW, a minimum of 5-8, broken in over time across all your training. As in, don't leave 1 pristine - make sure they all work over time and through a good number of cycles, before setting a couple aside for EDC.
For me personally, I'll be running this new gun hard over years, and large numbers of spare mags are a high priority for any gun getting worked that hard. I just picked up 5 factory mags and 5 additional MBX 19rd mags with Black Friday discounts. Given there are only 2 guns I know of that use this mag, just to be safe in case of future availability issues, I'll probably pick up another 5 or so in a month or two.
Also, be sure to number your mags - it never ceases to amaze me how many malfunctions occur that are just not obviously related to the mag. Yet, the same malfunction happens on the same mag, but you won't know that without numbering them.
I had these mag bases for a different gun laser numbered at a local gun shop for a few bucks each, and have been super happy with it, compared to labels or writing numbers on tape:
