If you've a large discretionary income present, it's fine to lump sum since the funds are available. Personally, I wouldn't lump sum with everything at once. I'll like to divide the money into 3 parts, lump sum with the first part, use the second part to increase my aggressiveness in DCA and keep the last part for buying my target dip.
The first and third parts are reasonable with me but I am not surely understand your point with the second part for aggressive in DCA. What's difference between aggressive DCA and dip purchases?
Aggressive DCA is showing more dedication and seriousness in your accumulation journey by buying continuously with as much good sum as possible from your discretionary income without burning yourself in the process. Dips are only rare opportunities to buy more quantities at lower prices and it might not be the best practice to strangle your DCA purchases with the hope that you'll catch a major dip.
I see the purposes of second and third parts are quite similar as you can wait for dips and take such chances for abnormal purchases with bigger capital spent for each purchase than normal DCA in a first part. I consider action of spending bigger capital for Bitcoin purchase whenever you see dip as better DCA chances than other times is aggressive buying.
Dips occur by chance and it's not something you just fold your hands and wait for before improving your game in Bitcoin accumulation, remember Bitcoin price is volatile and if you buy continuously you'll be able to buy at both highs and lows and increasing your aggressiveness if you're able is increasing your purchasing power to get more quantities per purchase which would amount to something tangible on the long-run.
IMO it's not a good practice to be whimpy in your DCA because you're accumulating funds for your target dip and what if the dip ends up not happening, then you'll have wasted time and chances waiting for the dip while you could've spread some of the funds across your buying period and if Bitcoin price continues going higher, you'll regret not being as aggressive as you could be simply because you were being unnecessarily conservative and waiting for a dip that didn't end up happening.
It's about proper planning and you've got to maximize every chance you've got to acquire more quantities of Bitcoin for yourself.