Those numbers seem quite high for shrimp. Gh 12 - most ranges for Gh I've seen for neocaridina shrimp are in the 4-8 range. Kh 6 - most seem to run <4, with most around 2. TDS 443 - you're going to hear that's about double the desired TDS. That's some hard tap water.
I, too, am new to this hobby. Several experienced people here will chime in to help. In all likelihood, you probably need to find a source for RO water and buy some sort of re-mineralizer for it. Everyone here will recommend Salty Shrimp - in hindsight, I probably should have gone down that road, but I am both stubborn and somewhat loyal to my LFS, who I would like to see stay in business, so I went with Seachem Equilibrium (more for plants, too much potassium for shrimp tanks) and have now settled on Sera Shrimp Mineral (what my LFS could order).
I hope this was helpful. Neos are supposed to be hardy, but I don't know how hardy in the conditions you've got them in at the moment.