an answer from barlop https://stackoverflow.com/questions/16596877/android-studio-doesnt-see-device/18515360#18515360 mentions that it's now in developer options
i can see developer options now, (And FWIW I turned on USB debugging). but they moved the sectoin to MTP from the 'input' section of developer options to elsewhere
To find the USB options now, there is a search within developer options, search for USB. Now it comes under "default USB configuration"
and you see USB controlled by, or USB preferences.. And it's there
And if PTP is listed but not MTP, then maybe what android may refer to as "File transfer" is the same as MTP. See my comment PTP but not MTP , this link https://www.xda-developers.com/install-adb-windows-macos-linux/ says "file transfer (MTP)” mode" which suggests to me that they may be the same. And BTW to install adb you probably also need the driver from the android sdk as mentioned https://windowsreport.com/windows-unable-install-adb-interface/ so you don't get a yellow exclamation mark for adb under "other devices" in device manager.