I highly recommend the mobile game shards of infinity, it is the mobile adaption of a competitive deckbuilder that was built by a former magic the gathering champion and designer of ascension. The gameplay is fairly simple (an evolution of star realms if you have played that) yet very strategic and once you play for awhile you begin to see how finely tuned it really is.
Also its just a digital board game, there are no microtransactions, ad infested bs.