Hey man,
Depending on if you are sleeving the decks and stuff, there are a few options that come to mind.
There's a company called Cardamajigs (
https://cardamajigs.com/) who make the kind of thing you are after. They're designed to emulate the idea of cracking packs for a cube (the product is called a cubeamajig) but they will likely be sufficient for what you want to. They have loads of options and work with some MTG artists so there are options with nice art on if that's your thing, or just plain ones if you like that.
They hold about 15 double sleeved or 40 single sleeved cards each. They're cheap individually (equivalent of about $2) or you can buy them in bulk and save on costs.
Not sure what shipping is like. I think they are US based so if you're not in the US it might not be worth it.
Also, if you are planning on sleeving them but need something a little bigger, there's the classic Ultra Pro deck box (
https://www.amazon.co.uk/Ultra-Pro-Trading-Storage-Gathering/dp/B00RKFB6WY/ref=sr_1_5?dchild=1&keywords=mtg+deck+box&qid=1603716785&sr=8-5). Cheap, effective, versatile, reasonably durable. Loads of colour options if you want to colour code. Little areas on each box to write the name of the deck if you want that kind of thing, but don't have to if you want to keep them anonymous.
I've used those little poker things you've linked and they're pretty decent. Unfortunately I can't quite remember how many cards they hold (sleeved or unsleeved) and don't have any to hand to check, but they offered reasonable protection and storage so might be perfect for what you are after.
Hope this helps. Let us know what solution you come up with. I've been debating doing a similar thing myself so would be good to hear what you end up doing and how it works out.