Last visit was in Delhi T3 and it was 30% occupied. There was no queue at entry (around 6 AM). Queue started building up post 7:30 but it was never more than 10 min of wait time
There's a new Rupay lounge (near gate 41). You can access it, if you find queue on the first one.
Accessed lounge last month. Stayed in for bit more than 3.5 hrs.
As airport is 300Km from my place, I keep 3-4 hrs of buffer time and often reach in time.
I have done 4+ hrs early checkin with AI & Indigo in Delhi airport. 6 hrs seems bit too early.
If you don't have any check-in luggage, you can do a self check-in & boarding pass and clear security.