That is fantastic news

Your pain is felt... At least you have Ivara, that'll make life much easier. OH SHIT, right... Important TIP.

The Challange saves after each successful mission you do. So if you get say... 6 in one mission without setting off the alarm then extract. It saves that 6, even if you get detected in the next mission it won't reset the 6 you already got, It just invalidates that one mission your on.

I'm Perin too so my medalions are super hard to see

I don't have Loki but I have Ivara. I can do it, it's just gonna be a massive pain in the ass

Next best chance would be running Loki and keep a very close eye on your stealth timer. As for finding the actual medallions... Bring a Loot Radar aura if possible... if not at least run some kind of loot detector mod.

Ouch, you'll have to skip any survival styled missions. (No Defense, no Survival, etc.) Otherwise... you'd be best bringing a Ivara designed for staying in stealth forever. As long as you don't de-stealth and no enemy triggers an alarm you'll be fine.