If you desperately need Android 10 or 11 features in 2021, the TB-X704F has a small but dedicated developer community. Unofficial LineageOS 17.1 (Android 10) and LineageOS 18.1 (Android 11) builds exist for the TB-X704 series.
Since Lenovo abandoned official updates, the custom ROM community stepped up. By mid-2021, stable Android 10 (LineageOS 17.1) and beta Android 11 (LineageOS 18.1) builds were available for the TBX704F. lenovo tbx704f android update 2021
While the Android 9 Pie feature update was the headline, 2021 saw a steady release of monthly and quarterly security patches for the TB-X704F. Lenovo typically follows a bimonthly security update schedule for its budget tablets. If you desperately need Android 10 or 11
If you are looking into this because of issues that arose in 2021, you are likely encountering one of the following: By mid-2021, stable Android 10 (LineageOS 17
Short answer: No. As of 2021, Lenovo officially stated that the TB-X704F will not receive Android 10, 11, or 12. The hardware limitations (2GB RAM, eMMC storage, and outdated Snapdragon 425 chipset) make a further update impractical. Android 9 Pie is the terminal OS version for this device.