For me, the benchmark is Venice Italy, and all of their canals, and all of the homes built alongside... if levels were rising, you should be able to see it there, easily. The harbor masters there have been documenting the levels for 500 years, before and after the Industrial Revolution, and the attempted Progressive takeover of "Science". The 500 year old homes built on and in the canals do not have flooded basements or any indicators of levels rising... in 500 years.
If anyone would be the "canary in the coal mine" for sea levels, it is THESE people, with their front door threshold within inches of the water:
