I downloaded Debian Buster a week or so back to use live on usb with persistence ; Debian is community driven with ethos for free software. I noted there is an iso missing wifi drivers and another one called "with none free" i.e it has the wifi drivers. Do you remember which one you downloaded. With an ethernet connection solution ( i'm guessing since wifi and power flaky here so no time to look at image) will be to enable none free repo in your mirror list