How many Arab League member states other than Palestine will diplomatically recognize the State of Israel as of 28 August 2021?
The Arab League consists of 22 member states (BBC, CNN, Arab League). As of 28 August 2020, three members other than Palestine--Egypt, Jordan, and recently the United Arab Emirates--diplomatically recognize Israel, though others could follow (France24, Economist, Whitehouse.gov). A suspended Arab League member diplomatically recognizing Israel would count (Guardian).
NOTE 2 September 2020: The question is framed "as of," so Egypt, Jordan, and the UAE would count toward resolution so long as they diplomatically recognize Israel as of 28 August 2021.