As you learn, keep your focus on this project/idea you'd like to build. Use tutorials and examples only to help you get to this goal; take detour as required. I think this approach will be easier to stay motivated with, than doing tutorials start-finish.
ESP32 is a popular MCU that connects to WIFI, and has cheap dev boards: I recommend you find a tutorial for this MCU to start with. A downside, is that its official docs are lacking compared to other MCUs, like the STM32.
Once you have something working using a dev board, learn PCB design software; a nice free one is KiCad. JLCPCB is a cheap, fast service that will create your PCB, and solder the smaller components on to it. You will have to hand solder the bigger ones.
Programming languages suitable for this are C, C++, and Rust. Are you proficient in at least one of them?