Citing the error message and its diagnostics again:

This may either mean that you upgraded your version of perl to one that is incompatible with your old dynamic extensions (which is known to happen between major versions of perl), or (more likely) that your dynamic extension was built against an older version of the library that is installed on your system. You may need to rebuild your old dynamic extensions.

So, you will need to make sure that your script(s) always invoke the perl 5.28 (under /usr/local/bin/perl), or recompile the Oracle DBD using your system Perl.

Personally, I recommend leaving the vendor Perl well alone as it belongs to the vendor and changes to it should only be made through the vendor or tools that the vendor has supplied. So the approach favoured by me would be to make certain that all scripts only use /usr/local/bin/perl and all paths only pick up Perl libraries below /usr/local/lib/perl5/site_perl/5.28.0 (and the other version-specific directories).