I think one of his first orders of business would be to make a good marriage for Elizabeth to one of the more powerful Protestant princes (and by prince, I mean any sovereign ruler of their own state, whether their title is king, prince, duke, count, elector, etc), while simultaneously arranging his own marriage with an equally lofty Protestant princess to secure a few alliances from the get go. I also see him harboring any and all Protestants needing protection from Catholic persecution, which would definitely make him some powerful enemies, while aggressively forcing through England's conversion to his brand of Protestantism. If he lives long enough (and if the butterflies allow for this) to see the 80 Years War begin in the Low Countries, I think he would more actively support the Protestant Dutch rebels there by sending more English troops over than Elizabeth did in OTL.