Let me explain what unique threat the blob poses:
https://securityaffairs.co/58656/hacking/intel-management-en...
I thought you were talking about proprietary microcode, which all of these chips you mention do come with. Or even worse, since they are all SoCs.... You'd have to e.g. avoid using the Ethernet controller on them (which generally has flashable eeproms with code) which would also happen to be an effective prevention of any ME issues even if were running an ancient version of ME.
I.e. the only threat vector you mentioned does not apply and can't possibly apply. A mac shares more firmware with your average intel laptop than this.