I don’t race anymore, only have one bike (2012ish Cervelo S2), and generally have only been riding in the spring summer. I’d like to get back out on the road more often and would need some fenders, which is something I’ve never tried to mount on this bike.
I’m looking for something fairly low profile and easy to install/remove. What’s the gold standard these days?
You may have trouble with clearence with fenders at all. A lot of the bikes of that era could only get 25mm tires in there on a good day. THE fork clearence is usually the deal breaker.
The SKS Raceblade Pro suits 20-25 mm tires, offers good protection and is easy to mount and dismount. Not sure how to check if your exact bike is compatible.
I tried the «AssSaver» thingie once and it came off first ride 
, may have been partly user error though.
https://www.sks-germany.com/en/products/raceblade-pro-black-2/
I’ll add another vote for SKS. While my Assaver was okay, it didn’t keep me as dry as my SKS mudguards. A ah
Edited to add that I’m on a bike with rim brakes, i.e. without a lot of clearance.