When downloading XAPK files from third-party sites, always ensure you are using a reputable source. Since version 87 is several years old, it does not contain recent security patches
The -Arm- flag is critical. ARM is the processor architecture for (Samsung, Pixel, OnePlus, Xiaomi, etc.). Download XAPK -Arm- -Android 8.0 - v87.3.4607.8...