Since stable ROMs are scarce, the best way to speed up this tablet is to stay on the stock firmware but remove the "ZenUI" bloatware. (if a compatible boot image is found). Frees up limited RAM.
The Asus ZenPad 10 Z300C uses an Intel Atom x3-C3200 (SoFIA) processor. This architecture is notoriously difficult for custom development. Unlike Qualcomm or Exynos devices, Intel SoFIA has very little developer support . Asus Zenpad 10 Z300c Custom Rom
If a developer eventually releases a "GSI" (Generic System Image) or an unofficial port, it will appear on these community hubs: Since stable ROMs are scarce, the best way
: For newer devices, users often use GSIs (Generic System Images) to get modern Android versions, but this requires Project Treble support (Android 8.0+), which the Z300C lacks. How to Revitalize Your ZenPad 10 The Asus ZenPad 10 Z300C uses an Intel