Domoticz

Hi All,
I have read the relevant topics (I hope so), but I could not find the solution.
I need to control 32 relays from Domoticz. Since it will be an essential part of a heating system, it needs to operate reliably for years. So I would connect 2 of 16 relay modules to the Raspberry Pi 3. The question is how?
I have some SN74HC595N shift registers in the drawer. Can I use them to multiply the output ports? But how can I control them from Domoticz?
Or should I use am Arduino Meg2560 and communicate with it through serial?
Has anyone some experience with a problem like this?
Thanks!

i would use the sonoff 4 channel devices with tasmota or node mcu boards with espeasy to do this, they connect to wifi, i have been using them for a year without any problems

I also have some sonoffs, but in this case it would be much too expensive for 32 relays.
Do you mean using node mcu with shift registers? I would be more happy if I would not need a wifi router between domoticz and the relays.

Maybe the piface offers a solution. You can link a maximum of 4 (= 32 outputs) to the rpi. I have been using 2 pifaces for years with great pleasure.

I have found an ethernet module as a possible solution: https://www.ebay.com/itm/253147442957
It can control the modules like these: https://www.ebay.com/itm/192530066391
It can be easily integrated with domoticz virtual switch.