I took quite some time to find an answer for your question. I don't think it was possible to answer it before the Winter Update 2024, because the information about damage was hidden. However, I always thought that the damage was calculated using both physical damage + elemental damage.
For example: a Winterblade has 10 physical attack + 40 ice attack which results to = 50 total attack.
With the Winter Update 2024, now we can go to our character page on Cyclopedia and analyze all of our stats. And my theory was indeed correct.
Look:
On example 1, I'm using a Soulshredder, but I'm level 202, so there I have 198 levels less than the minimum required to use it. After I put it on my weapon slot, it doesn't give ANY attack from Equipment, so the effect means that Soulshredder's attack on my character is 0 (Zero):
Note that even with a 0 attack weapon, it still says that the Converted Damage is +83% ice, which means that it converts that percentage to ice damage regardless of which attack value I have.
Now let's take a look on example 2, where I use Winterblade and I have the minimum recommended level:
Note that the Attack value that comes from Equipment is 50, this is the final result if you add 10 physical + 40 ice.
And finally, let's take a look at example 3, which I use a Tagralt Blade with minimum level 250 recommended (48 levels difference):
It has 7 physical attack + 49 earth attack = 56 attack. If we do the math, 56-48 = 8 attack.
So answering your question, you lose both damages, because they are calculated together. The damage you do with any weapon will always be calculated based on converted damage + attack value that you get from all sources like level, skills, weapon attack and wheel.
A Cobra Club will lose 7 attack value if you use it being level 213, but you will still get the converted damage from it's element.