Call me naive, but as VAST as our oceans are, I couldn’t imagine even melting ALL of the ice on the planet moving the sea levels all THAT much. I think it would be about like dumping a typically sized bag of ice into a near full bathtub.
The stuff that’s currently afloat in the Arctic would have ZERO impact, you’re right. That one can be shown with some ice cubes in a full glass of water and some time to let them melt, but the idiotic moronic jack-holes who advocate for the political nonsense that is AGW can’t even get that one right.
Much of the ice setting on Antarctica is likewise below sealevel, and if that ice melted, sealevels would actually decline just a bit.
Isostatic rebound of Antarctica and of Greenland would deepen the ocean basin as the landmasses rose, raising capacity a bit, and reducing the overall rise in sealevel — but that’s only in the event of all the ice melting, and that isn’t happening.
Despite the warming that is known to have gone on, on a recurring basis, over the past 2500 years or so, Antarctica has been covered with ice for millions of years (how many millions is a matter of dispute). The leftist trolls who drone on about the allegedly horrendous problem of AGW like to emphasize that millions of years idea, trying to make AGW look like a real problem but all it does is show what complete a-holes they are.