Importing PDF

I import complex vector based plans (created in programs like Vectorworks or other CAD programs) which either crash Corel 2017 or are extraordinarily slow to import and then quite impossible to work on due to semi-consistent freezing.  My IT contractors have been out yesterday to ensure my PC is capable of handling these files and have advised this is not a hardware, memory or graphics issue. the pdf's vary in size from around 130mb to 1GB however again my contractors advise this is ok.  They believe the problem lies in an incompatibility with Adobe pdfs.  They downloaded 3rd party conversion programs also with no resolution. Non complex files have no problems importing or being manipulated/edited.  Does anyone happen to know if this is an issue that has been resolved in the 2020 version?  If so I can just update the program.  With thanks. Sam.