I have always used the New Century Schoolbook font in LibreOffice (and OpenOffice before that) and got "curly quotes" (U+201C, U+201D) instead of two vertical lines (U+0022) with the quote key. Now font C059 (replacement for New Century Schoolbook) or any other font I've tried just give the plain quote U+0022. The closest I've come is a font like IM Fell Double Pica, which gives the U+201C character, but doesn't have eye appeal. I want my curly quotes back, but I'm stumped.

System:
Kernel: 5.8.0-44-generic x86_64 bits: 64
Desktop: Cinnamon 4.8.6 Distro: Linux Mint 20.1 Ulyssa
LibreOffice 6.4.7.2

You can set quote options in tools-autocorrect options-localised options to your liking. Also your libreoffice is ancient, current version is 7.2.2

Hmm, C059 has glyphs for “curly quotes”. What is the version of the font you're using?

A glyph C059 doesn't have is U+201F DOUBLE HIGH-REVERSED-9 QUOTATION MARK.

Anyway, would you mind them being replaced by corresponding glyphs from another font? Say Nimbus Roman?

Edit. As lvm_ says above, this is not a problem of the font, but of the correct LibreOffice settings.

I thought I had already tried the "tools-autocorrect options-localised" idea without success. Turns out I didn't use it correctly, so all is now well.
Thanks to all.