It depends what material you're tying. For twine, sure; if you're hanging a 30 kg artwork you probably want to use steel wire, and pretty much any kind of knot is unsuitable here.
Get some 2 mm Dyneema rope, which has an average breaking strength of 300 kg, run it through some D-rings and tie it with an Alpine Butterfly. You will be able to do pullups off that artwork if you want.
Oil rigs are towed to location using steel cables. Steel wire rope is substantially stronger for its weight and for it size but generally harder to work with than plastic things of similar capacity. Both materials can hang pictures just fine. It's not exactly a dynamic load. People will argue over anything.
That is not true. The tensile strength of kevlar and dynema is higher than that of steel, while they have a density that is several times lower.
Platform anchoring cables are often a rather complex combination of synthetic cables and weights to obtain neutral buoyancy.
But when it comes to UV and chemical resistance, I don't see how one would get any degradation in a museum setting. Dyneema is used in heavy industrial applications like mooring lines and tugboats for very large ships with lifespans over ten years. Unless you're hanging up something that you're not taking down for a century, it shouldn't be a worry.
To add to this; this is the vast majority of art.
Steel cable will slice people in half and send wrenches through car windows and to stab the driver when it breaks.
Why I won’t drive over the cable car slot. Slice cars in half, that.
For better or for worse steel is often used instead of synthetic rope for picture hanging.
First, you can tie knots with steel wire, too.
Second, I would be much more comfortable hanging artwork on a thin twine than on steel wire. Steel wire tends to be sharp and scratch and punch holes in anything it gets into contact with. Rope that will be durable and can withstand the stress of hanging 30kg artwork is still very thin. Just google it and be surprised. (https://www.ingersollrand.com/pt-la/lifting-equipment-materi...)