Hi everyone!

I could really use some advice about which TP-Link Deco unit to get next. I currently have two Deco devices at home: a Deco X10 (placed in the middle of my single-floor house) and a Deco E4 (placed by a window facing the front yard).

My internet speed is around 80 Mbps, and my main goal is to extend the Wi-Fi coverage outdoors – specifically toward the backyard. I don’t want to use outdoor units (they’re too expensive), so I’m looking to place a third Deco unit by a window facing the backyard.

👉 My budget is around 1500–2000 CZK (~60–80 EUR) per unit, not for a full set.

What I’m really struggling to figure out is:
What specs actually influence range the most?
Is it the number of antennas? I just don’t know what to focus on.

And finally, the big question:
Is it better to buy more cheap units like the Deco E4 and slowly expand coverage bit by bit?
Or is it smarter to invest in fewer, but more powerful units?

For example: if the internet speed isn’t that high (like mine – 80 Mbps), is it better to have ten cheap Deco units spread all over the house and yard? Or will two or three stronger units (even if they're 3× the price) always give better, more stable coverage?

Thanks so much for any insight – I really appreciate it! 🙏