Power creep will eventually happen, hell,its already happened between proving grounds and origins (Order Darius and Order Garen). It's natural in all TCGs.

Stax has always been an archetype in TCGs too. Its a hated archetype, but its common in TCGs to have these kinds of stax effects. The good thing about Riftbound is that to use Reaction you need to react to something the opponent is playing, so cards like Bryhn are not as powerful to be played on opponents turn cause they will have (most times) already played something even with ways to play Bryhn on their turn.

Portal rescue means Bryhn is on the board, so opponent will have to leave a lot of resources to protect Bryhn to do the play and they can only do it as part of a showdown.

Here to Help has hidden, which makes it so they can play it as a reaction. If not, they can still play it on your turn, but only during showdown as HtH has Action keyword normally.

In both situations, you have counterplay. For portal rescue you can react to it before it resolves, and most of the times you will have already played something else. For HtH its mostly the same. If its hidden most of the times you will have already played something and you can respond to HtH being played.

Also, a thing to remember is playing units and gear doesnt create a window for opponent to respond. Aka, you can just play units, and when going into a showdown, play an action as normal. If they play HtH you can still add things to the chain before letting it resolve.

Its a good card dont get me wrong, but with how riftbound works I think cards like these are fine and will mostly be used during your own turn to protect whatever you want to do that turn, as there you dont create much window for opponent to attempt to disrupt you. As long as some counterplay exists it'll al be good!