Based on this product's specifications, here are some alternatives and similar models
Battery for HUAWEI Mate 20 HB436486ECW 4000mAh Li-ion by extra digital
Summary description:
Internal replacement battery compatible with HUAWEI Mate 20, model HB436486ECW, 4000mAh Li‑ion capacity. Intended as a spare or replacement to restore original runtime and device mobility. Suitable for use when original battery shows degradation, reduced charge retention, or abrupt shutdowns. Requires professional or careful DIY installation following safety guidelines.