Guppies can hunt and eat the baby shrimp - so hopefully, the plants are providing enough cover for the babies.
What is your GH? And temp?
KH doesn't have anything to do with how hard or soft your water is, only helps to control pH - which does not tell you how hard or soft your water is.
If this tank has Fluval Substrate in it (or similar - I'm not familiar with the "Premium Aquarium Soil" you shared pictures of), and you are adding KH, that could be a part of the problem... that is, if the substrate is still active. Fluval substrate is a buffering substrate meant to lower the pH of the water by means of absorbing KH from the water column and adding in humic or tannic acids. Each time you add more KH to the tank, you are causing unstable water parameters.
If you are doing water changes more than once a week that could potentially be another issue - many shrimp keepers do water changes once a week or less frequently.
If the "algae pellets" are actually animal protein based instead of, well, *algae* based (most "algae" pellets are really just algae infused, not algae based), that's another potential issue.
How are your living shrimp acting? Any pictures of them?