DnD: Roll for Initiative!

To elaborate in the last session our group played we went up against a mini boss. It was overall a very fun fight but the DM introduced a mechanic where three times a round the enemy was able to do a special dodge where our entire attack is negated.

The way the mechanic works is that after the players have hit they will ask how much damage we do then decide if the boss dodges or not. This ability was separate from the enemy's three legendary actions. One which was an aoe attack which was actually pretty effective and cool against the melee fighters, and the second was literally called "earthquake nuke" which did 6D10 to everyone. The boss also had 700 hp and the party is currently level 7.

To be completely fair we do have a party of 7 players which I understand is very hard to balance for.

In the end we were fine, our party made it out with not permanent deaths. It just left a bad taste in my mouth. I think it is a cool mechanic but it did feel kinda bad whenever we used any player ability to increase damage or rolled a nat 20 it was always dodged. I can see this being a fun strategy thing to get around but it defiantly lessened the "epicness" of the fight. Basically it felt to me like we were punished for doing good damage.

I do wanna hear other people's thoughts tho bc I am aware this is from the perspective a player that likes to beat shit up. Are there any other ways this could be implemented but less punishing? Or is this good as it is and I am being a salty player? Or other ways a DM could make encounters harder than this.

I didnt want to bring it up to the DM yet bc I don't want to be a difficult player- so I'd like to hear your thoughts on this.

Edit: Thanks for all the helpful feedback! I don't think I explained the ability that well, so for further clarification the "dodge" they used was a reaction the enemy had and they had another ability that allowed them to take three reactions per turn. And the dodge was automatic👍

I'm pretty sure it was a one time thing as far as I know, but I'm not certain. Also the boss was bard/rouge themed so I think they were supposed to be evasive and tricky. So I think the ability fit, it just has some not so fun draw back imo.

I've seen a lot of people saying maybe it could be changed to be more like uncanny dodge were it haves damage and that's a good solution, there are probably more to. Like maybe having something similar to the shield reaction that wouldn't apply to nat 20s or really high attack rolls. Which are pretty creative tweaks I may bring up to my DM

I mostly wanted to bring it up to see some other opinions and maybe have a talk with my DM about why I was a bit bummed. I honestly think they came up with a pretty fun idea but probably should be tweaked. I don't think they made the ability up to spite us players or anything, our group is large and probably takes a lot of work coming up with a solutions for that. And they are very receptive to feedback and aren't malicious. But it did feel a bit upsetting as a player in the moment.