I would just like to make a point here.
And also, welcome
You can try to save this plant (and the other).
Get rid of the bad roots.
Repot it into better media and hope for more roots.
Chances are, given some TLC, you have a reasonable chance for success.
But I don't care if you bought these plants ON SALE!
Why would they mislead you into thinking they were "okay"?
I would take them back and get a refund!
...or at least request and exchange with some other orchid there and insist on looking at the root system before you take it home.
I have gotten to the point where I look at my own plants and think ... bleh! my root systems could look so much better!
Then I go to a place that SELLS orchids and nearly flip to see that their root systems don't even hold a candlestick to mine
Really, why should you pay the price for someone else's neglect.
Unless that is your "thing"...and for some ppl it is and I respect that.
But not for me