Is sea erosion the opposite of sea level rising (or rather, an adjacent phenomenon)?
A paper about this was published yesterday in Nature Climate Change: Sandy coastlines under threat of erosion (Vousdoukas et al. 2020).


  While shoreline change can be the combined result of a wide range of potentially erosive or accretive factors, there is a clear cause and effect relationship between increasing sea levels and shoreline retreat, pointing to increased coastal erosion issues. Climate change will also affect waves and storm surges, which are important drivers of coastal morphology.


The study computes projections of shoreline retreat. They computed four projections: two for 2050, and two for 2100, depending on climate change scenarios (RCP 4.5 and RCP 8.5). Here are the results:


  Assuming that there are no physical limits in potential coastal retreat, by mid-century we project a probable (5th–95th percentile) global average long-term shoreline change, ranging from –78.1 to –1.1 m and –98.1 to 0.3 m, under RCP 4.5 and RCP 8.5, respectively (negative values express erosion). By the end of the century the erosive trend becomes even more dominant and we project a probable range from –164.2 to –14.8 m and –240 to –35.3 m under RCP 4.5 and RCP 8.5, respectively.


And here is how it looks on a map (their figure 1):



The caption reads: 


  Projected long-term shoreline changes. a–d, Projected shoreline
  changes by the years 2050 (a,c) and 2100 (b,d) under RCP 4.5 (a,b) and
  RCP 8.5 (c,d). Values represent the median change and
  positive/negative values, respectively, express accretion/erosion in
  metres, relative to 2010. The global average median change is shown in
  the inset text for each case, along with the 5th–95th percentile
  range.


Note that this projected retreat is a combination of two factors: the ambient shoreline change (AC) driven by geological, anthropogenic and other physical factors, and the shoreline retreat due to sea level rise (R). But R is the dominant factor, with a worldwide contribution of 82 % to the total retreat (with regional variations, see their figure 2).

In summary, climate change leads to sea level rise, which in turns leads to coastline erosion. Sea erosion is not the opposite of sea level rising, it is a direct consequence of it.