MNL doesn’t have a shower and it’s cheaper just to “buy in” (25usd ish) with cash/card than pay the Priority pass fee (32usd). Personally, the Starbucks in T1 is more tempting than the lounge (I’ve used it too much to know it’s underwhelming).

Do check whether you need to change terminal in MNL.

Curiosity - what’s the planned itinarery in VN?