Absolutely​‍​‌‍​‍‌​‍​‌‍​‍‌ large CSV files have the potential to break various converters, mainly online ones. I had a CSV file containing close to 5,000 contacts, and most of the tools that I tried ended up freezing or exporting incomplete VCF files. The method that I found to be effective was OSTtoPST CSV to VCF Converter, largely because it handles big files comfortably and gives you a preview in a structure. This way, you can be sure that there are no missing rows before you proceed with the export. The mapping stage of the fields also gives you the option to make sure that all the columns are correctly aligned so that your CSV to VCF conversion is exact. In case you are looking for a dependable method to convert CSV to VCF for a large amount of data, this tool is better than the web-based converters and is the right way to go as a CSV to vCard ​‍​‌‍​‍‌​‍​‌‍​‍‌converter.
Read more info: https://www.osttopstapp.com/csv-to-vcard.html