@bites You should replace Ethernet cable which links Main Deco to ISP modem/router.

@Benwood118 It is called QoS. You should set this parameter values to 600 for download and for upload. See this: How to set up QoS on the Deco If that does not help and speed is 90, replace Ethernet...

@MJ-UK You can connect Deco devices with Ethernet. This topic is discussed here: General questions about Ethernet Backhaul feature on your Deco Scroll down to Q4 in that document, it answers your...

@a_sh Thanks. Will wait on your update for #1 and #4. For #1, ISP Router brand and model name can often be found on the label on the bottom of the router. Please also do the following two...

@Don_Bro You can add Deco X50-Outdoor to your Deco E4 WiFi mesh and they will run together. It would make sense at some point to also replace E4 with 3-unit set of Deco X50 or Deco X55. This will...

@RonMid Short answer: it is not possible. Long answer can be found here, in discussion of all TP-Link WiFi mesh offerings: TP-Link Deco Mesh vs EasyMesh vs OneMesh vs Omada Mesh What's the Difference?