@Kevin_Z 

Ok wow.  Do you hade a design choise that no one would ever want to upgrade your perfect antennas?  Utterly ridiculous.  You can add this to the growing list of reasons I will never again buy a tp link product.  I may just throw this POS away and move on,  Had super trouble  connecting and doing port forwarding nd now I wnt to boost my internet speed you want to sell me an extender.  WEll lets just look at that.

First off, im sure you know a wifi extender without an ethernet backend actually slows the speed?  You may get a nice speed connection to the extender, bu by it's nature an extender like that halves the practical bandwidth as it has to both listen to the main device then repeat that to the further devices.  That's goof to creating signal to another room maybe but screws you on throughput.  You can get round that with a cable extender from your cable company and they will likely speed you up and extend range as they get their backend over the cable line (Docsis) but that works with their equipment.

Next many of the extenders on the page you referenced have speeds of 300 or 500.  We're talking wifi 6E ax here so that really doesn't cut it.  It's offensive you would even offer it as a suggestion.

Next some powerline might work. They can claim gig speed.  Note these are not WiFi extenders which would make them useless to OP and just something the company wanted ti throw out there,  There is this (link deleted TP Blocked me from showing you a link to the items THEY LINKED THEMSELVES ABOVE)  Another stem to ensure you don't know the truth.  This is fast it seems.  Subject to old house wiring Jumping over breakers etc, and gain this is just a WIRED solution.  So you can plug your laptop into an Ethernet work, but that sorta defeats he point of a laptop.  So you could then get an extender that uses an ethernet back end.  So you;re looking at about 200 euros for that power line.  God knows what for the extender and how much aggravation.  

As just Marilyn Milian on Peoples court says, the cheap comes out expensive

Could just replace the antennas with high gain antennas but NO your company went out of its way to make the antennas  non removeable.  Could there be any lopgical reason why you would make it impossible for the consumer to change?  Maybe this is why your quality equipment is being sold bargain basement at WalMart  Anothiner friggin company with non consumer friendly policies who thinks they know better than me,and that they think they can get you to buy just a little bit more to make your POS actually functional.