My impression is, you had a cool idea - i absolutely agree! And you realized it - which not everone achieves, so honestly: patt yourself on the back, really. You also layed the foundation would could become a cool game, for instance: there is skills, pieces, you can select them (card-like interface at the bottom) etc. All you need for the mechanics. Even the music is there, and I like it - very relaxing and still stimulating with a rich melody. Well chosen! I have some issues with the game, though:
What I don't get is why you have to select move versus attack. The pieces work like in real chess, so, there is no need to let the player have to click on attack versus move. Selecting a piece and the destination should be enough, because empty tile -> move, opponent there -> attack.
The health bar is a valid idea, but I must admit I don't like it at all, because it breaks all the strategic fun of the game - BUT: this is just MY opinion. I might include a health bar only for exceptional cases, i.e., all pieces have only 1 HP (not 4 HP) per default, but some skill (or neighborhood to some other skillful piece) would extend this pieces HP from 1 to 2 HPs. In that case, this piece is in an exceptionally healty state, and then the HPs would be more interesting. Again: just my personal opinion. You don't have to agree.
Pawn reaching the end of the board -> no conversion, that's ok, but then there should(?)/could be something else.
I saw a tile destroyer skill, but I was not allowed to use it somehow. Anyway of this issue, but hey, these skills sound like the real fun. Also make obstacles on the board, maybe randomly and also by the players. Also skills to transform tiles from ground to water and then allow some pieces to walk through water and other not. Stuff like this could make the RPG-ish chess more fun.
And yes, the AI opponent... woah, that is actually not easy to do well. This might become a hard challenge. But I agree with the Dragon... that in the current state the game is ways too easy and thus looses the challenge and fun to play.
BUT, as I said at the start: I like the idea und you laid the foundation for making a cool game. Keep the motivation and experiment with the potential you have. Looking forward to next versions. You can use the TheWoodlander's discord server to inform us and discuss with us.