No. In accordance with instructions here on TidBITS (thank you, @frederico), I put the following addresses in the DNS lookup table on on Airport Express.
1.1.1.2
1.0.0.2
2606:4700:4700::1112
2606:4700:4700::1002
I just checked and those addresses are still present (and the only DNS addresses shown).
I’ll start shopping. Would you recommend Eero for a new purchase?