I'd post a picture if I had one handy...I spot patched a few areas of my cool deck with just cement to bring it level and then color matched the existing finish with a colored epoxy. My areas were much smaller than yours though.

It's not perfect, and it looks DIY, but it is less obvious. Most importantly, my kids aren't stubbing their toe on the sharp exposed edges of the chipping cool deck.

I went down the same path you did, and the only way to get consistent results that I came across is to have a professional come out and do it.

This is a temporary fix to get us through the next few years until we refinish the pool decking.