That's not a stupid question. I had to ask myself the same question and now I can answer it. Yes, you need a DTU. The DTU has two transmitters/receivers, one is the WLAN protocol and the other is the proprietary protocol to the inverter. However, there is an inexpensive open source solution. You can find the instructions for building it yourself on the Internet at technik-zeilen and search for ahoydtu. Provided you have a bit of electronic tinkering experience. Good luck.

Yes, as has already been written, you need DTU or an open source solution. With the open source solution, your data does not necessarily go to the Chinese cloud. If you only want to know the production output, then you could simply install a Shelly 3EM, for example, and monitor the total production. However, you won't be able to communicate directly with the microinverter or change the parameters, if that is necessary at all.

The HM-600 communicates on a proprietary 2.4 GHz protocol (Nordic). It does not communicate with WLAN. With the Hoymiles DTU-WLite you can communicate with up to two alternating directions and max. 4 solar inputs. If you can solder, the OPENDTU NRF kit from shop.blinkyparts.com product number: blink237542 is a good option. This costs less than half the price. The housing is included. You get online access via W-LAN and a display with real-time intervals without the Hoymiles Cloud.