I use an offline PC as a cold wallet. It works in combination with 2 USB drives: the 1st has Tails OS; the 2nd has my key files, a copy of MyCrypto desktop, and my encrypted account info. I can sign an offline transaction for later broadcasting on a separate connected PC using this set-up. Problem is, I can only do ETH transactions. I'd like to perform similar transactions with ERC20s (specifically, Dai) with this type of solution, but without having to buy a hardware wallet or smartphone.
For example, suppose I transfer some ETH from my cold wallet to a hot wallet, use the hot wallet to purchase some Dai off a DEX, and then finally deposit this Dai back into my cold wallet. What is the best approach to then transfer the Dai from the cold wallet back into a hot wallet using my set-up?