How do I change my Wi-Fi speed to 2.4 g on my iPhone 13 Pro MAX?

That is controlled by the router it is connected to. If your router has two frequencies it will usually have two SSIDs or a menu choice.

Could you explain your situation and requirements in a little more detail?

2.4 GHz is a band, with various channels, and various different Wi-Fi network speeds are available within that band.

Which Wi-Fi band and which channels within the band you can and will connect to (2.4 GHz, 5 GHz, and 6 GHz) depends on your Wi-Fi hardware and your hardware configuration, and depends on your physical location.

Your Wi-Fi router will offer an SSID Wi-Fi network name, and your Wi-Fi client will connect to the client-accessible channels available with that SSID on whichever bands are available on both the Wi-Fi client and the Wi-Fi router.

One Wi-Fi network can offer one channel in one band, or many channels across the available bands.

If you need to require a channel in 2.4 GHz, then you’ll likely need to reconfigure the router to offer a SSID for that channel or channels.

2.4 GHz wouldn’t be my usual choice generally, as that band tends to have more interference than does 5 GHz or 6 GHz.

*Apple isn’t offering Wi-Fi 6E and 6 GHz quite yet.

Dragnfli wrote:

I will check my router - I am trying to sync some light bulbs and they do not work with 5 g . Thank You for the prompt response and Merry Christmas!

So long as your Wi-Fi router network name (SSID) is configured for and broadcasting at least one 2.4 GHz channel, the Wi-Fi should be compatible with these 2.4 GHz devices.

Do you have a dual frequency router?

Did you bond the 2.4 and 5 Ghz into a single network connection?

Are you having connection issues?