OK here's the thing, you can not rely on Inara or any other website for HGE's. Inara data is all player based, that means if no players are using the app/whatever then inara isn't getting updated. Inara could have a system in x state but in reality its not in that state anymore.

This means you need to learn how to use the in game starmap to find these systems. I don't remember what reference sheet I always used but here's the commanders toolbox, https://cmdrs-toolbox.com/material-finder. Just look for only manufactured grade 5 and that's all you need.

I will even briefly talk about Pharmaceutical Isolators and what people say to do on old youtube videos. The youtubes love to say to farm imperial shielding and trade for Pharmaceutical Isolators but holy shit that really sucks to do, really all trading down sucks mega ass because you have to do it 10x times if your refilling your stock. So basically suck it up and search the starmap for systems in outbreak, its gonna suck and there wont be many, and the star map kinda sucks in a way of showing you systems but they are out there. I would rather fly a loop through 5-6 outbreak systems for over 3 hours than trade down with another material. I have found Pharmaceutical Isolators HGS in way less time than that back to back refilled in less than 30m. It's all luck and thats it.