As a noob early in his music production career i bought a bunch of theese foam absorbers with high hopes of them fixing my lowend response in a bigger 40m2 single room apartment.
Ofcourse they didn't, material isnt thick enough to reduce anything other then highend reverb, which in fairness they work fine for.
Thing is, even if you can use them for a reverbated room they aren't that pleasing to look at after a while.
Do yourself a favour and get the real stuff, either from thomann or Hofa. Sucks spending money on soundtreatment, but you only have to do it once.