It's possible at the retail level, but you have to have enough equity to support the loan collateral. If you have 15MM+ you can do it. There are more than a few people on this site who are retail guys trading that big.
everyone can take a margin loan with a margin account with enough collateral, this isn't the discussion.
We're getting off topic here.
OP said he'd rather take a 100m loan at @ 3% (floating) to stake into a 10% yielding (crypto or smth) project instead of buying outright underlying (crypto ccy) for 100k. Now, I really wanna see that happening

Not to mention the absurd of comparing 100m with 100k. As if 100k collateral would get you that 100m.
and please dont compare eurodollar margins to crypto margins (this is to whoever posted that, cant remember)