First boot takes 3-5 minutes. Do not interrupt it.

: The Reno 6 5G uses a MediaTek Dimensity 900 chipset. Generally, MediaTek devices have less community development support compared to Snapdragon-based phones, resulting in fewer available ROMs even if the bootloader could be unlocked.

You cannot do this through official Oppo channels anymore. Your only options are:

Finding a custom ROM for the is extremely difficult because OPPO typically does not provide official tools to unlock the bootloader for this specific model.

Download the custom ROM you want to install on your Oppo Reno 6 5G.