The very popular Sunwayfoto PCLO-R5 Arca/RRS Compatible L Bracket (for both EOS R5 and EOS R6) is back in-stock. This one-piece L-bracket is compatible with Arca tripod mounts, enables access to all ports, and has built-in bubble levels. A limited quantity is back in-stock for $49.95 at Amazon (sold by 3rd party but fulfilled by Amazon), and is Prime eligible.
(Not to be confused with the Sunwayfoto PCL-R5, this recently released PCLO-R5 is a one-piece construction. The PCL-R5 is also a great product to consider as well, and currently in-stock at Adorama.)