What the heck did you do to that poor A7? I've ran them all from A721 up to currently A10's and all have been damn near bulletproof despite some running in very hot (>95F) areas.

That said, ALL miners run hot especially these days. Personally I'd stick with Avalons like the A11 or A12's.

An Avalon A8 series can run at 9TH around 900W - great quiet room heater in winter if you slow the fan down
And in LowPower mode with the rest default settings it should be fine not getting too hot.
It's original firmware allows you to adjust it easily.
... and of course you can use the RPi, power supply and cables that was running the A7 before
Just get the firmware direct from Canaan themselves who makes the miner:
https://download.canaan-creative.com/

Before you proceed to buying hardware for the next mining use, you should pay attention to temperature and pressure needs assessment, electricity consumption, and this hashing power is important to sterilize the current you use on the device so it doesn't burn easily.

Try to check Bitcoin miner hardware like:
* Pangolin mining 12Th/s.
* Antminer S9 13.5TH/s.
* Dragon Mint T1 15TH/s.
* Avalon6 3.5 TH/s.

You can choose one of them for you to use the minister is often used quite practical and thick, not flammable.
Between the four also differ in quality and also voltage, you can adjust one of them for your use.