Wifi dongle / Volumio 3 and update 3.198, REALTEK 8811CU

here the answer to your question

the only difference is the file to be written, instead of adding the two followings lines on config.txt, add them to userconfig.txt, so they will be maintained with OTA software updates

dtoverlay=disable-bt
dtoverlay=disable-wifi

If you’re going to edit the userconfig.txt file inserting the SD-card to a windows PC, please don’t use notepad, but install and use notepad++ to edit the file