Is PDFTron compatible with .net core?
Yes, it is possible to run PDFNet.dll under .Net Core.
Please note that PDFNetNoLoader nuget package is not from PDFNet, though the assemblies are.
Most likely the easiest way to run PDFNet under .Net Core is to not use AnyCPU, and instead use x64 or x86 configuration and load the corresponding assembly. Or target the 32bit assembly, mark copylocal to false, and then “manually” copy the 64bit.
Finally, if you do try to use the PDFNetLoader.dll, that is will only work with .Net Core 2.0 (as earlier versions are missing the required reflection API).