What OpenWrt version is best for MIPS64 Dual-Core Processor?

I am planning to use Openwrt for the first time. I have an old router lying around that I want to flash with Openwrt.

Now my question is which version of openwrt should I use for my router.

The router has the processor: MIPS64 Dual-Core Processor CN5020-SCP 300MHz 2Core and 32mb flash memory.

Thanks in advance!

If it's not here, it's not supported.

32 mb flash, or RAM ?