Search for "Project Treble GSIs" to find generic Android builds compatible with your model. Stock EMUI 9/10 Generic System Image (GSI) Stability Low (Bugs with SIM/Camera) Performance Laggy on 2GB RAM Faster, but prone to crashes Updates Discontinued Up to Android 11/12 Installation Easy (OTA) Very Hard (Testpoint/mtkclient)
Custom ROMs often improve performance by: Removing background bloatware. Using lightweight system UI. Optimizing RAM usage. Prizm Institute 10 Best Custom ROMs for Android You Can Install - Beebom custom rom for huawei y5 2019 top
There are virtually no device-specific custom ROMs for the Y5 2019. Instead, developers use Generic System Images (GSIs) because the device supports Project Treble. LineageOS (GSI): Search for "Project Treble GSIs" to find generic