If you want to buy the cheaper old ones and are concerned about heat just add a usb fan. I have the same mikrotik switch in the post and 2 sfp to rj45 + this fan https://www.amazon.com/dp/B00G059G86?th=1 sitting on top and it makes a dramatic difference in temp.

I appreciate the craftiness of this but with the years I stopped being a fan of Frankenstein setups. The vendor should be honest; if the piece of tech is expected to heat up, just add a fan to it and manual toggle and a knob to control it or have it work auto.