As someone who have years in arknights gacha can say it is good. The biggest joke is that Hypergryph company behind Arknights creation is a music company and then Gacha and etc. So music direction is always great in all PV for events or character songs. I would say they first season bit lore heavy and is worst in terms of story, mostly rough start of gacha story that was revised. Second season and Third is where the peak of AK storytelling... There is a lot to cover storywise so 3rd season won't end Chapter one (out of 2 which ending soon on CN, global is behind as typical gacha but by 6 months only).
So moving away my bias as gamer and purely on anime. I would say it's decent and good if you can close your eyes on some aspects. The minus are typical anime tropes of child protagonist, amnesiac main character, child is face of the organization. Pluses would be that it is really grounded world building with big premise on suffering of incurable disease and treatment of poor/ill/different race and even specific racism against one race.
So give it a thought, if you enjoyed a bit first season then second will be even better.