This article reports the development of ferroelectric tunnel junctions (FTJs) based on samarium-substituted bismuth oxide (BSO), achieving a giant tunnelling electroresistance (TER) of up to $7 \times 10^5$ with a 1-nm BSO film, three orders of magnitude higher than previous reports. The BSO-based FTJs demonstrate 32 distinct resistance states without write-verify techniques, high endurance ($>5 \times 10^9$), high linearity of conductance modulation, and long retention (over 10 years). A TER of over $10^9$ is achieved with a 4.6-nm BSO layer, surpassing commercial flash memories. The high TER is attributed to efficient barrier modulation by the large ferroelectric polarization, and the barrier height/width modulation at the surface depletion region of the semiconductor. These BSO-based FTJs support multi-level cells and analog memories, with 5 bits of data storage in a single device. The results show high potential for reliable, high-performance, and low-power non-volatile memories and in-memory computing. The study also highlights the importance of maintaining ferroelectric stability and minimizing depolarization fields in ultra-thin ferroelectric layers. The BSO-based FTJs exhibit excellent endurance, retention, and device-to-device variation, making them promising for large-scale integration. The research demonstrates the potential of BSO-based FTJs for next-generation non-volatile memory and computing applications.This article reports the development of ferroelectric tunnel junctions (FTJs) based on samarium-substituted bismuth oxide (BSO), achieving a giant tunnelling electroresistance (TER) of up to $7 \times 10^5$ with a 1-nm BSO film, three orders of magnitude higher than previous reports. The BSO-based FTJs demonstrate 32 distinct resistance states without write-verify techniques, high endurance ($>5 \times 10^9$), high linearity of conductance modulation, and long retention (over 10 years). A TER of over $10^9$ is achieved with a 4.6-nm BSO layer, surpassing commercial flash memories. The high TER is attributed to efficient barrier modulation by the large ferroelectric polarization, and the barrier height/width modulation at the surface depletion region of the semiconductor. These BSO-based FTJs support multi-level cells and analog memories, with 5 bits of data storage in a single device. The results show high potential for reliable, high-performance, and low-power non-volatile memories and in-memory computing. The study also highlights the importance of maintaining ferroelectric stability and minimizing depolarization fields in ultra-thin ferroelectric layers. The BSO-based FTJs exhibit excellent endurance, retention, and device-to-device variation, making them promising for large-scale integration. The research demonstrates the potential of BSO-based FTJs for next-generation non-volatile memory and computing applications.