outdoorsiness
Having embraced my indoorsiness for years, I was astonished to find myself developing a love of nature.
What you are describing is not just indoorsiness, it sounds like agoraphobia.
The success of TV streaming platforms seems directly related to our indoorsiness.
I was struck by these young people's indoorsiness and their open declarations of how little they knew about the environment.

SMART Vocabulary: related words and phrases

Shy and modest
aw shucks
backward
bashful
bashfully
bashfulness
humility
inadequacy
inadequate
indoorsy
inhibited
mousy
reticently
retiring
self-conscious
self-consciously
self-consciousness
shyness
unassuming
wallflower
withdrawn