I was looking for a owners manual to read and found this. Looks like replacing the battery in the future won't be too bad. I'll cross my fingers and hope that the bootloader is unlockable.
Open Source Code
Lenovo TB-X705F_USER_S000017_20180831_Q00020_ROW Factory ROM [androidhost.ru].zip
Lenovo TB-X705L_USER_S000023_20180921_Q00020_ROW Factory ROM [androidhost.ru].zip