First of all, most of the temperature rise only happening close to the surface with average surface temperature rise being only about 1.5F or 1C since 1901.
This article says deep ocean water is projected to warm up by only 0.2C during next 50 years: https://www.openaccessgovernment.org/deep-ocean-warming-subt...
Furthermore, at around 4C which is what deep ocean water is close to (everything below 200m is essentially 4C), thermal expansion is almost nil. For colder water thermal expansion is actually negative.
4C is when water is at its densest. It is not an accident that all oceans are 4C, because 4C water sinks to the bottom and anything colder or hotter than 4C floats up. This remarkable property of water is what causes even shallow water to be fantastically stable in temperature -- a lake that has more than couple tens of meters in depth is likely to be 4C at the bottom throughout the year whether it is frosty winter or hot summer above it, unless some kind of powerful event is able to mix the water in the lake.
Now, the small temperature differences will definitely have outsize effects on water circulation, ocean currents, life and weather. But I doubt they will cause meaningful sea rise unless somebody can calculate otherwise?