Thats my point england will be doctrinally catholic just different head and assuming this continues to influence edward then it likely goes the same as before catholic but with the king as head. Unless he dies llike otl in which england will have a smoother transition back ender mary with less die hard protestants. However if he continues to rule then more of the same.
But, with the Church of England nominally Catholic, that leaves a lot of room for the Mistress, (Catherine Parr or whomever), to influence Henry towards a more Protestant leanings.
And on your point about mistresses coming and going, with Henry stuck with Jane, the antithesis of his type, I could easily see a long term mistress. This mistress wouldn’t have to have a lot of influence, just more than Jane which wouldn’t be hard.
Also, without Mary being re-legitimized (since even if Catherine Parr is the mistress she’s not going to champion Mary and Jane doesn’t have the chops to get mary re-legitimized) and Jane having another son or two, Mary is never sitting on the English throne.
So, wether slow or fast, unseen Henry, Edward or Edward’s heir, England’s heading towards Protestantism.