I don't think Hardman brings anything to the table that Chark cannot. Marginally faster but doesn't play with that speed for whatever reason. On the flip side Chark has better ball protection, a huge size advantage, and some critical receptions when it matters the most. Also a 1000-yard season in recent history is a nice plus unless it inflates the contract. Hardman has never shown anything to be more than a #3 at best but Chark has better potential.
I would prefer a solid possession receiver to help Kelce over both these guys but if we have to choose I think the Hardman experiment is not worth dragging any more.