this is what most RW4 owners use:  https://amzn.to/3WHpOmc

Looks like the safety notice was updated to include all tires with ribs near the rim:

QuoteAfter further investigation, we identified another tire quality issue on some RadWagon 4 ebikes purchased which may lead to an increased risk of flats. Depending on the results of the inspection we ask you to conduct below, your RadWagon 4 may require replacement parts before it is safe to ride the bike again. We will be providing complimentary parts and service by a local ebike mechanic to repair both issues.

Please stop riding your RadWagon 4 and inspect the tires on your RadWagon 4 according to the instructions below.