Many high-tier cards are rewarded through A-Rank Technical (TEC) victories rather than just Power (Power) victories.
Even with the boosted drop rates, Achieving an A-TEC (15+ fusions, 4+ effective attacks, usage of magic/trap/equip cards, and winning with less than 7000 LP) remains the most effective method for high-rarity drops. Yugioh Forbidden Memories Mod 15 Drop List
Alternative source to Jono 2nd.
Pegasus is the priority target for altering the battlefield in your favor. Many high-tier cards are rewarded through A-Rank Technical
For the best results, you should aim for an rank in either POW or TEC. The drop tables for S-rank are significantly better, containing almost all the most sought-after cards in the game. Achieving an A-TEC (15+ fusions