I don't believe cheap cabs sound cheap. I feel the speakers are more important.
Out of all the cabs I've owned or played the best sounding cab I've ever used was a Peavey MS412 with a back panel made of MDF which everyone talks crap on. The speakers made the cab.
With that said these days swapping speakers is nothing more than a pain so if I had the extra cash I would buy the cab you want with the speakers you want already installed.
There are definitely good sounding cheap cabs out there and I played one cab made all out of mdf that I loved (super punchy sounding), but IME many cheap cabs I’ve played have been awful, so you gotta do your homework to figure out which ones are good
IME great speakers don’t save an awful sounding cab and some cabs like my Ubercab has such a strong character to it that it still seems to have the same type of sound no matter what speakers I put in it. Not complaining since I really like the cab, but it’s almost like an EMG effect it has, while some cabs I have became radically different with speaker swaps