If you want to downgrade the rom, first think of the "anti rollback" lock of the straw on Xiaomi.It broke my partitions, I am now 100% stuck in fastboot.
I will now try to flash the fastboot ofw... I hope it will fix it.
EDIT: This fastboot ROM saved my renoir: renoir_global_images_V12.5.5.0.RKIMIXM_20210805.0000.00_11.0_global_9f22a26eac.tgz