It is unlikely that it is possible to convert SME SMS backups to VCF contacts files. You need to obtain full backup of your smartphone in order to extract the contacts from it.
Convert Samsung Kies SMS backup to vCard contacts.
We found 2 software records in the database related to .sme to .vcf file format conversion.
Microsoft Windows software - convert sme to vcf on Windows
A free software for managing of latest Samsung mobile devices
Convert from sme file format
The tables with software actions are a good pointer for what a certain program does with various file types and often may give users a good hint how to perform certain file conversion, for example the above-mentioned sme to vcf. However, it is not perfect and sometimes can show results which are not really usable because of how certain programs work with files and the possible conversion is thus actually not possible at all.
Apple macOS / Mac OS X software - convert sme to vcf on OS X
Management and sync utility for Samsung mobile devices