One thing I noticed was that after recovering the assets and database onto a test server (see this) , the performance of the replica NodeBB install was painfully slow. After much searching and hair pulling, I found that the indexes seemed to be missing - a point which is referenced by NodeBB themselves here
When I checked /api/recent
it was indeed slow - like a snail. So, at their suggestion, I opened up mongodb
and added the missing indexes
db.objects.createIndex({ _key: 1, score: -1 }, { background: true });
db.objects.createIndex({ _key: 1, value: -1 }, { background: true, unique: true, sparse: true });
db.objects.createIndex({ expireAt: 1 }, { expireAfterSeconds: 0, background: true });
The difference is quite astonishing. Now it runs like the Ferrari I’ve come to love and respect 
Might be useful for someone else in the same boat…