I think the more likely scenario is they are fakes, pressed with benzodiazepine analogues
Yes exactly this, go check out wedinos a lab that tests people's drugs, I'm not saying send yours pills to them as you need to be in the UK I think, but just have a look at their website and check out xanax and other benzos they get sent, so much Flualprazolam and Etizolam etc
I've had so many white xanax 2 mg bars, they look exactly what was on Google images, when I was first buying them they was definitely real xanax but they was fake in the sence someone had either repressed xanax but made them weaker, bought xanax powder and pressed their own and mixed it with another powder, such as chalk or something, nothing sweet as most people dissolve them or chew them up to get the Alprazolam taste, as that's how we see how strong they are, we see how bitter they are as alprazolam has a distinctive taste
So yes yours are probably fake, they may have alprazolam in, but also another compound, another benzo, likely an RC like ones ones I've mentioned or other RCs, or if you're unlucky fent!
Best thing you can do is buy fentanyl testing strips and test a piece of your pills