Discuss: SIP vs Lumpsum when Lumpsum amount is quite huge compared to SIP

Can anyone share their insights on which investment strategy is better in following two cases?

Prerequisite: SIP amount is X per month. Initial idle cash sitting in bank is more than or equal to 36X ( 3 years equivalent amount of SIP per month)

strategy 1 is to do lumpsum of 36X amount and continue the SIP of X amount per month

strategy 2 is to increase SIP amount to 2X and continue with that amount till 36X is used. After that, continue the SIP with X amount only.

P.S. Not looking for suggestions to park the lumpsum into debt or other things since that is already done. Need insights on which strategy is better in what conditions?