Even if you assumed that, you started at step 1 and didn't think past that.
Let's assume China pays the tariff. Is China going to eat that? They will probably pass it onto the seller.
OK now what? Let's say before the tariffs, their total unit cost is $5, and they sell it to you for $10 (I'm just making stuff up here).
Tariffs were 145% at some point. So China pays $14.50. China passes it onto the seller, now the total unit cost is $19.50. They lost $9.50.
Are they in the business to lose money with every sale? No.
However, that presents a problem. The tariff they paid? It's higher than the price they sold it to you. That will remain the same regardless of the price you have to pay. Even if they charged you $1mil, they could not make a profit, because the tariff would be $1.45mil.
So, yeah, you were very much wrong. The idea is not only unrealistic, it is mathematically impossible if the goal is to actually make money when tariffs are 100% or more.