I'm using this
https://www.youtube.com/watch?v=DQumISxkJsQ to send funds, however I'm wondering if I can avoid using 2 computers and perhaps 1 computer, 1 usb and 1 phone (Electrum works on Android, but I have an iPhone) with the hot wallet for fund top ups and daily spending. Without a phone having a USB port, I imagine I would have to manually type in a key or perhaps a QR code?
You need two computers for Electrum to work properly in a cold storage environment. One for signing transactions and holding your keys offline, the other for creating and broadcasting transactions. There is no way to get around that and still have the security that an airgapped computer provides. Other combinations can work, but we are no longer talking about having your signing keys in cold storage in that case.