Airplay stuttering with Airport Express joined to Orbi network

I have an Airport Express (Model MC414LL/A - dual-band 802.11n) set to join my wireless network created by the Orbi system (RBK50).  The Express and the Orbi satellite are within 15 feet of each other.  The satellite indicates it has a good connection with the base.

Unfortunately, when I airplay to the Airport Express, the audio cuts in and out (stutters).  This does not happen when I airplay to the two Apple TVs in my house (both of which are connected by ethernet to the Orbi Base Station).  Unless I use a powerline kit, I do not have a way to hardwire the Airport Express to the Orbi Base Station.

Am I missing a setting that may improve the airplay capability - in either the Airport or the Orbi?

Would a powerline connection between the base and the Airport improve the airplay?

Thank you.