What do you mean non-wifi? You particularly don’t want to use defined wifi protocol? Obviously you have to use some kind of radio transmission unless you want to use tin cans and very long string, and wifi is the easiest/cheapest/simplest. There are alternatives such as dji lightbridge and similar non-dji alternatives (which usually also carry mavlink), or you can use 4g/lte. You’ll have to say a bit more of what you want/don’t want for more information.