Now, you got me quite confused:
The protocol parameters are in https://github.com/cardano-foundation/CIPs/tree/master/CIP-0009. Relevant for this are maxTxSize = 16384, minFeeB = 155381, and minFeeA = 44. According to https://docs.cardano.org/explore-cardano/fee-structure, the (minimal) fee for a transaction is a * size(tx) + b.
So, the absolute maximum should be 155381 + 16384 × 44 = 876277 Lovelace, 0.876 ADA.
I have no idea, why your Daedalus builds transactions with more than that. And I also have no idea, why it sometimes takes two inputs and two internal outputs, leading to even higher fees.
You could try to get answers from IOHK support. I’d be interested.