I often see players arguing over which character is a good damage dealer from a particular element. If you want to compare characters, you should compare them on their ability basis and how well they synergize with your available characters. Yoimiya is indeed a good character and can output severe damage to the enemies paired with decent off-field damage dealers. Other pyro characters like Klee, Diluc, or HuTao specialize in their own playstyles. They have numerous damage combinations that you can follow.  One tip would be that if you are focusing on meta characters, then always see how well a character will fit with your existing roster of characters. Some of your characters may have constellations unlocked and require you to tweak your team according to their playstyles. So, if you have good off-field damage dealers, I recommend you go with Yoimiya. My choice is to go with characters who have area-wide attacks because I prefer to play the spiral abyss most of the time, and it has multiple enemies. Higher floors may have only a couple of enemies. Still, I just prefer to play characters who have area-wide abilities.