how do I uninstall sonoma 14

It is not easy possible to downgrade macOS, you might want to see this link and follow the instructions provided to troubleshoot your wifi problems

If your Mac isn't connecting to the internet over Wi-Fi - Apple Support

Well, this is the procedure: Create a bootable installer for macOS - Apple Support

But if you're not very comfortable after reading the FULL article, I suggest the other posters have the appropriate solution.

Lots of chances in the procedure to completely brick your computer, so don't take the task lightly.

Before you go to the trouble of downgrading the system give this a try: boot into Safe Mode according to How to use safe mode on your Mac and test to see if the problem persists. Reboot normally and test again.

NOTE 1: Safe Mode boot can take up to 3 - 5 minutes as it's doing the following; 

• Verifies your startup disk and attempts to repair directory issues, if needed

• Loads only required kernel extensions (prevents 3rd party kernel/extensions from loading)

• Prevents Startup Items and Login Items from opening automatically

• Disables user-installed fonts 

• Deletes font caches, kernel cache, and other system cache files

NOTE 2: if you have a wireless keyboard with rechargeable batteries connect it with its charging cable before booting into Safe Mode. This makes it act as a wired keyboard as will insure a successful boot into Safe Mode.

This is a very poor idea, what you need to do is to troubleshoot why your computer will not connect to any website. Start by unplugging your router for 2 minutes, then restart it and then restart the Mac and retest.