I have a WH1080 running with an RPi2. Purchased an Ecowitt system to replace it, with both HP2551 display and a GW1000. Bought extra sensors (outdoor temp + humidity, 3x indoor temp and humidity, 1x soil moisture). You don't need an RPi4. It runs hot and is overpowered for what you need. A Pi2 uses much less power and you can pick one up 2nd hand for cheap. My only complaint, and it's not
really a complaint, more a matter of aesthetics, is that the soil moisture reading on the HP2551 spoils the symmetry of the display, so much so that I decided not to bother with it (it was an experiment anyway). You can get some useful background info on Ecowitt and rebranded and other alternatives at
wxforum.net