Here are my two cents on range extenders. They are great in a pinch, but have some huge disadvantages.
Keep in my that each time you extend, you halve your speed. There are a few exceptions to this (as there are with all technical things) but this could become a concern. There are also differences between boosters, repeaters and extenders, so know what you need and are purchasing. Get some basic information here:
If you do go the Extender route, tray to match the equipment you have. This is not necessary, but using an Asus Extender with an Asus Router may have some benefits. These could include better performance due to testing by manufacturer, lack of issues due to chipset conflicts, etc.
Depending on the investment you want to make you may want to consider a MESH WiFi system. I am retired from an IT career and I use the EERO PRO system. It is simple, fast, takes little technical knowledge and has Ethernet ports. The service also has year paid add ons offering security and other services which may or may not interest you.
I guess this is an product endorsement (unpaid, unaffiliated, etc.). I do not have anything on my dislike list for the EERO system. I do like the automatic updates, easy monitoring from my smartphone, Ethernet ports and coverage/speed. I am done playing with tech, I just want it to work.
Finally, just to add more to the list, you can also look into PowerLine Ethernet if you have the ability to take advantage of that. https://www.digitaltrends.com/computing/everything-you-need-to-know-about-powerline-networking/
Hope this helps.