Where Meaning Actually Comes From
Meaning is produced, not located. It appears reliably where three conditions overlap: work that uses your actual capability, a constraint that makes the work non-trivial, and an effect on someone other than you. Change any one of those and the sense of meaning weakens — which is why it can vanish in a comfortable, successful life.
Why comfort erodes meaning
Remove the constraint and the work stops testing you. Remove the other person and the work stops mattering beyond you. Comfort tends to remove both at once.
Rebuilding the conditions deliberately
You can reinstall each condition on purpose. That is a design task, not an existential one.