Sea levels have certainly risen over the thousands of years, even hundreds. It’s not due to an increase in the amount of water...nor is it due to the warming cycle over the last few decades, or century and a half. It’s much longer term, as the oceans are huge.
Some rise, some fall. The 'sea levels' rise on one coast, yet fall on another. Yet it is all 'point of view'. It is not the water that is moving, it's the land.
Excluding the tides and winds, and short duration natural landfall events, the average sea level around the globe has not changed significantly in a long, long, long time.