Hello  @Kiezelke ,

As Woozle noted, when it comes to wireless extension devices, more is not necessarily better; wireless signals are highly susceptible to environmental interference and experience significant signal loss during transmission.
Of course, given your existing equipment, you could start by adding some range extenders and testing their actual performance.
If the results are unsatisfactory, I recommend considering a wired connection instead. Alternatively—particularly if your network coverage area is extensive or includes outdoor spaces—you might want to consider upgrading to higher-performance business-grade products.