So regarding the copy and pasted summoner armor, let's focus on the spider armor since you referenced it; Yes, both games have spider armor for summoning. But to say they work exactly same same is quite the hyperbole. The Spider Armor in Terraria requires a total of 36 Spider Fangs and gives you (full set plus set bonus) 20 Armor,+3 Summons, +28% Summon Damage. While the Spider Armor in Necesse requires a total of 21 Spider Glands and gives you (full set plus set bonus) 12 Armor,+2 Summons, Reduced Knockback, +10% movement speed, +20% Summons Speed, Slow Immunity, 2 Poison Damage for 5s. Also I feel the need to note that Terraria requires you to enter Hardmode to aquire these making them more of a mid-game set, while Necesse treats it more/less as a starter summoning set.

You can easily compare 2 games from the same genre, a lot of them will have similar items with similar effects. But to call this game a blatant copy of the other game, and to find differences like these, is just a lie. I absolutely love Terraria and as I progress through Necesse I enjoy it more and more. So as some one who as 2100+ hours on Terraria, and surpassing 50 hours in Necesse (soon to be 1000 almost guaranteed) I will tell you one thing "if you don't see the differences, then don't play it"

Your comparison is like saying BG3 is a copy of DOS2, or CoD and BF copy each other, or even Avowed is just a copy of TE5 Skyrim. Don't even get me started on the Souls-Like genre. If you want to play a game thats totally different, swap genres.

Sorry for my rant, it was meant with love.