if the oil pressure is low it very well could be the reason the turbocharger is failing
been through this many times, most recently on a 2.3L Ford (SVO). Ate a turbo. Figured the turbo was worn, so I had it rebuilt. Ate that one. Hmm. Called the rebuilder, he says it was perfect when it left (and it probably was, knowing him). He said check oil pressure. 15 psi at 2500. 10 psi at 1000. It had a oil light but it doesn't come on til 5 psi or lower. Engine ran fine.
on turbo selection, be careful. The compressor wheel and turbine wheel and turbine housing may very well be different, which might result in no or low boost, or high egt, or whatever. These little engines are really sensitive to that stuff. Maybe send yours out for a rebuild. I'd personally do that before I bought an unknown chincanese turbo. If that chicom turbo fails, it sends the impeller through the engine. Not sure I like that thought.
a tiny bit of play in the shaft is no issue on hydrodynamic aks "journal" bearings which is what yours is. IMO if it ain't leaking any oil into either of the housings, I ain't worried about it.
but I'd certainly put an oil pressure gauge on it, just so you know.