New Phalaenopsis with many bloomed offshoots; how to care?

[pharaoness]

I just bought this new phalaenopsis orchid from Home Depot on sale for $10. The reason for the price reduction is because the blooms began to wilt on one offshoot of the spike, but two offshoots still have blooms, and altogether it still looks nice!

I want to make sure this one safely ends its blooming period and re-enters it healthy, as my last one did not fair so well (nearly died, still in recovery and I'm hoping it will survive).

I've attached pictures that show the entire orchid, it's multiple off-shoot spikes (still has a few blooms, but must be at the end of its cycle as wilting has begun), and a close up of the rooting medium (the moss is only on top, below is all fir-bark).

First, I'm wondering how I should treat the multipe spikes once the blossoms all drop, because I want it to bloom the same way (multiple offshoots in bloom look beautiful), so I don't really want to cut them off... What is the best way to proceed?

I'm aware that it definitely needs to be repotted (the pot is FULLY rootbound), but I won't disturb it until it has completely ended its flowering cycle. Just for my own knowledge, are the open roots at the base okay like that? I'm assuming they are this way because it doesn't seem to have aerial roots now?

I have it in a west-facing window (all windows face west in my apartment), I live in Toronto Canada, the temperature is about 15 C or 59 F daytime, 7 C or 44 F at night. It receives indirect sunlight. I water once a week (or as needed) on and off with fertilizer (19-31-17 from Schlutz), and mist (not the blooms) every other day.

Also, any tips on the current state of my new Phal? How to keep it blooming (if possible), what to change, ANY input/feedback would be greatly appreciated.

Thank you so much for your time!