A few developers on XDA-Developers and 4PDA attempted:
No public, bootable, free Android 10 image exists for RK3188.
While most RK3188 threads are dead, check the "Android TV Boxes" legacy forum. Look for LineageOS 17.1 ports. These are the highest quality but rare. rk3188 android 10 free
The most active community for legacy Rockchip devices. Search for your specific device model (e.g., "RK3188 Android 10 4PDA"). You will need to use Google Translate. Look for threads with "Android 10" or "LineageOS 17.1" (which is Android 10).
There is no complete, free, working Android 10 ROM for the RK3188 due to insurmountable hardware and kernel limitations. Any claim otherwise is either a scam, a fake version string, or an unstable proof-of-concept that cannot run real apps. The last usable freely available Android for RK3188 is Android 7.1.2 (LineageOS 14.1). A few developers on XDA-Developers and 4PDA attempted:
Appendix: If you wish to attempt building Android 10 for RK3188 yourself (academic only), you would need to:
No report can change hardware reality. Consider upgrading your hardware. No public, bootable, free Android 10 image exists for RK3188
A guide for installing Android 10 on an RK3188 device for free requires a significant disclaimer: The RK3188 is a very old chipset (circa 2013), and there is no official Android 10 support for it.
Getting Android 10 on this device requires using custom ROMs (often ported from similar Rockchip SoCs like the RK3288) or specialized builds from the open-source community (such as LineageOS or "Superior OS").
Here is a comprehensive guide on how to approach this, where to find the files, and the risks involved.