@Bob.58
It is not recommended to use an extender with a Mesh network.
If you want an inexpensive add-on Mesh node, buy a Deco M3W
https://www.amazon.com/TP-Link-AC1200-WiFi-Range-Extender/dp/B07Q2WQWT7/ref=sr_1_4?crid=2HUBUVOOKB6DW&keywords=deco+m3w&qid=1670682362&sprefix=Deco+M3W%2Caps%2C141&sr=8-4
or a refurbished single DecoM5 node
https://www.amazon.com/TP-Link-Deco-M5-System-Single/dp/B07P12YNLG/ref=sr_1_6?crid=2HUBUVOOKB6DW&keywords=deco+m3w&qid=1670682443&sprefix=Deco+M3W%2Caps%2C141&sr=8-6