No prob, love talking about this card game. Literally made that screenshot earlier because folks on Reddit were asking for my deck list after explaining that 30 wins got you an NPC's card sleeve.
I guess to add on to that for the "card combos" you were asking for since I apparently saved a bunch of replays when fighting Harmony. First replay is about how the cards are very well-situated for chaining a bunch of special points with the splat bomb specifically, or other similarly small straight cards. The majority of the cards are strictly straight lines with little in the way of diagonals, allowing you to better position them to be in the perfect spots to be completely filled by a well-placed Splat Bomb. This one in particular was basically overkill on the combo I made, generating 5 special points with a single card, but it demonstrates the basic idea of what you should be aiming for towards the endgame in order to end with special points for a powerful special.
View: https://twitter.com/DerpyVivi/status/1569810905214627841?s=20&t=__EaZ9CmFpGr4pU2DZT8nA
Next up is the use of Stinger, or any similarly long card like the Splatanas or the Splat Charger, to both cut off the opponent and keep your ink on their turf. They all have good distance while still being an aggressively low block count, allowing you to win direct confrontations and keep the area in your favor. In this replay, Stringer managed to both completely seal off the area from Harmony, while still keeping some ink on the her side, allowing me to claim more of her turf on the following turns.
View: https://twitter.com/DerpyVivi/status/1569813024634183680?s=20&t=-3VN0fJojbxFvyijTFNaAg
Finally, here's a two parter from the same match, focusing on both the Splatana Wiper, or similar two-special small cards and ending on special cards, which are all the cards named after specials (Inkjet, Tacticooler, Wavebreaker, etc.) that all have great point to block ratio (only 3 special points for 12 blocks) at the cost of having no special point themselves. In the first replay, Harmony managed to cut me off pretty well, so I was forced to use a special to break through her turf. Because she was convinced that area was safe for that turn, she focused on the left area of the map which was still contested by me, allowing me to start placing cards in her top turf area.
View: https://twitter.com/DerpyVivi/status/1569816814301106177?s=20&t=3JBIyQCRHwedaolUGNno3g
She still had the advantage in overall blocks at this point of the match up until the end, but this move kept me in a competitive spot to overtake her on the final turn. She was up 84 to 72, but because I had saved up 3 special points for the final turn, I could unleash inkjet for a potential 24 block swing towards the end, which I knew she couldn't counter because she went into the final turn with only 1 special point, resulting in a win for me with 83 to 75. So the general flow of the endgame is to find a way to guarantee 3 special points by the last turn with your special in hand, even if that involves passing a turn which will result in passively generating a special point. Keep in mind you can only use a special from a special point block, so position some cards in a way that their special point is directly next to enemy turf.
View: https://twitter.com/DerpyVivi/status/1569817197295595520?s=20&t=3JBIyQCRHwedaolUGNno3g