Hi. Have you reported this to Evernote Support, with example notes?
I can usually copy and paste note content from a note to a Word document without any difficulty, unless the original source was (forinstance) a web page with unusual protections or coding. Worst case I can use the URL information in Evernote to visit the original source of a note and (usually) copy directly from there.
Evernote has been 'hinting' for some time (with the big bold red flash across window titles) that Legacy Evernote was replaced 3 years ago and is no longer supported.
Your original note content is still available in your account if you upgrade to the current version. Exporting, Copying and pasting into other software should not be an issue, but if it is, we may be able to help you work around any problems in the forums. You can also report them to Support, who may - in the longer term - be able to fix them in future updates.