Please share your Cornered strategy tips

When I play that variant I don't know what I'm doing. Please share your strategy tips.

Don't let the opponent's knight break through your pawn structure, since most of your pieces are short-ranged or can only move forward. If the xiangqi knight comes in, you can trap it (hopefully) but maintain a good pawn structure.

Sergeants are the most valuable piece

Openings, typically, involve pushing pawns on the "brick" side of the board to ready the bishop for development.

Keep the outer king and horse near the outlet so that they can defend from attacks from there. I'll also recommend that, at some point in the game, move the inner king onto the hill square to assist in defending the outlet

The promotions are key try to get the pawns promoted if possible

I'd suggest promoting to a general in the middlegame and a rook in the endgame.

This way, while in the middlegame, your general can wreck havoc in your opponent's position, as the rook lacks the diagonal moves it need to defend itself in the middlegame. However, in the endgame, the rook is the better promotion option since the rank to checkmate your opponent is less defended.

Usually if you have an open 3rd rank, you want to promote to rank because you can get your rook backed by the commoner to mate, which always happens in most cases, meaning that rook promotions are mostly better.

Here's some things that I do in my games that I think might be helpful for you:

Avoid weakening your pawn structure without a clear benefit. However, remember that piece activity can sometimes be worth a pawn structure sacrifice. Attack your opponent's pawns to create weaknesses, which you can then exploit.

If you have a material advantage, exchanging pieces but keeping pawns is good. Advance your passed pawns and use your king effectively in pawn endgames. Rooks behind passed pawns are also strong.

Utilize your center pawns to establish and maintain control of the central squares. Bishops can alse be effective from squares like b2/b7 or g2/g7 for long-range central control.

We're talking about Cornered, not standard chess. But good standard chess advice, though.

This includes sacrificing pieces.

I have found (though I may not be the most reliable source on this) that sacrificing a piece to safely promote, no matter what piece it is that is being sacrificed, will always be the best option.

Since the whole point is promoting pieces, removing a king or bishop will not hinder your position if you gain a rook or general for it.

However, if your opponent responds with their own promotion, while being up material, you just might be screwed, depending on the position.

Sergeants are worth 5-6 points, having the most promotion potential

That’s probably an “it depends” sort of statement

depending on how far pawns are, the more valuable they are. You don't want to offer trades with your pawn 1 or 2 squares from promoting with a pawn that has not moved or has barely moved (exceptions apply).

30 kings vs 1king an queen

... not the place for that