As of 2021, there are 3 excellent options:
KDE Connect (Open Source)
Scrcpy (Open Source)
A step-by-step guide to setup and configure KDE connect, Airdroid - https://digitalfortress.tech/misc/wireless-file-transfer-between-android-and-ubuntu/
I'm guessing your doubt is about how an Android SmartTV have some info about Linux...
Surely you have saw this Linux info into Settings>About TV and this info is about the Linux Kernel version built-in the device.
The stock recovery can only make use of ADB for sideloading of packages under the "Apply update from ADB" option in recovery. You cannot perform any other adb tasks.
Also, the issue that you are facing is mostly related to emmc which has gone into a r/o mode probably due to its lifecycle being all used up. As such, it is impossible to mount the ...