This must've took a while to do, especially if you did it so cautiously. Respect!

Good to know, cheers

I definitely did use Cyrus to help with clearing buildings and destroying large groups of enemies. A lot of it comes down from using your units correctly and levelling/equipping them properly. As well as clearing enemies quickly and sequentially before they can deal any significant damage to your units. Here is the guide I used that gives lots of good advice: https://steamproxy.net/sharedfiles/filedetails/?id=3204884280

Impressive. I played for maybe three or four missions on Sergeant difficulty and noped out because bosses were way too spongy and insta-killed too easily. Did you abuse invisibility and/or save-scum? I feel like it's borderline impossible without one or the other.