3:05 and onward on the link I sent.
They show/ Probably it's based on your level first and foremost. Higher level rewards higher mod tiers. Rest is just RNG, but chances are probably slim.
I also remembered - you wrote smth before about fleet shipments resets to get more wedge shards. I would be against it. It resets 3 times a day and you do get a lot of useful shards there, regardless. Especially considering you're starting out. I would't invest so much into fleet shop resets.
Edit: Yes, that link was the one I read, on reddit. Maybe they nerfed mod shop as well, idk.