Adding 1 more Slot?

Apart from 3 slots (1 artifact, 1 ?, 1 ring) I feel there's a strong need for another column which will also provide much needed expansion for backpack to store few more items too.

But my focus is on the additional slot. Is it fair to have one? I know people will quickly find it problematic on game balance were we allowed to have more but can't there be something interesting that doesn't offset the challenge?

My suggestion is to have 1 more SLOT exclusively for artifact!

BUT it becomes permanent and can't be unequipped to ensure player chooses carefully with consequences in mind. Also this slot becomes available after defeating 2nd boss.

This will solve a major issue I have playing as Rogue or finding a good artifact drop later in the game and prefer not to swap existing artifact after upgrading them to maximum

I am also open for any other use case for 1 more SLOT apart from artifact

Would like community views on this question