9th beta released October 6th, 2021. Build 21A5543b.
As per beta7 and beta8, I had to temporarily use SMBIOS iMac17,1 to complete the upgrade and avoid the boot loop problem since I'm using older bootloader versions (Clover r5133 and OC 0.7.0). Other than that, all Ok on my Latitude E7270 (Clover) and Toshiba Satellite R50-B (OC).