So should I state in my store's T&C that I am not the supplier but merely the mediator? Does this statement alone has any power to reduce my legal accountability for the product's safety/functioning?
You're missing the point. No matter what you put in your T&C nothing prevents somebody from filing a lawsuit against you if they are injured by any of the products you sell. Even if you are not liable for the injury you still have to defend yourself against the lawsuit. That means hiring a lawyer because you can bet that the injured person will have one. It could take many months and tens of thousands of dollars in lawyer fees before you are absolved of liability. You may never have to pay a nickel toward somebody's injury because it's the manufacturer that generally takes the hit for a defective product. Unfortunately, the cost of defense will eat you alive and that alone could put you out of business and into bankruptcy.
And lest you think that an LLC or corporation will protect you, understand that a personal injury attorney will name you as an individual along with your company and you'll still incur defense costs.
If you want to avoid that kind of debacle you buy Products Liability Insurance. As a drop shipper, the risk of you being liable for somebody's injury is very low so the cost of the insurance will also be commensurably low. And if nothing else, your insurance company pays for any litigation defense costs, should litigation occur.
Find yourself an independent commercial insurance agent who can set you up with the proper liability insurance.