Hardware for easy Nord Pool automation at first, HA integration for more complex automations later?

The goal: I’m looking to optimize electricity consumption and automate 5 electric appliances (water heater, electric heaters, underfloor electric heating, all in the range of 1500-3000W) according to electricity market prices (Nord Pool). Initially, I’d like to create a simple on/off switch automation. For this purpose, I’m looking for 4 smart plugs and 1 smart relay.
Later, I’d like to add temperature sensors to develop more sophisticated automations with HA.

Shelly Plug and 1PM seem to be a good fit at first (can create a script in Shelly Cloud, later easily integrate devices to HA), but I want to avoid WiFi devices.

What would your hardware recommendation be for someone just starting to build their system? Are there any good hardware alternatives based on Z-Wave or ZigBee that I could automate at first with their app/hub and later integrate to HA? I would also like to avoid flashing devices.