Font Management is not an available option under Settings, Appearance, Fonts. I am running KDE Neon 5.22, KDE Plasma 5.22.5. Please advise. Thanks.

Seems to be fine on my system at:

System Settings > Appearance > Font Management

Operating System: KDE neon 5.22
KDE Plasma Version: 5.22.5
KDE Frameworks Version: 5.87.0
Qt Version: 5.15.3
Kernel Version: 5.11.0-37-generic (64-bit)
Graphics Platform: X11
Processors: 16 × Intel® Core™ i7-10700 CPU @ 2.90GHz
Memory: 15.3 GiB of RAM
Graphics Processor: NVIDIA GeForce RTX 2060/PCIe/SSE2

Would suggest:

1) update to KDE Frameworks 5.87
2) try a new user