I'll analyze the winrate of Simic Midrange decks with and without Quantum Riddler in Modern.
Let me check a wider date range since there's very limited recent data:
I don't have sufficient tournament data to answer this question.
The database only contains 5 Simic Midrange tournament entries total, and none of them include Quantum Riddler in their mainboard. With such limited data, I cannot provide a meaningful comparison of winrates with versus without the card.
Quantum Riddler appears to be either a very recent addition that hasn't seen enough tournament play yet, or it's not being adopted in Simic Midrange lists that have been recorded in the database.
Sources: Data from 5 total Simic Midrange entries across all available tournaments (most recent from September 2025). None included Quantum Riddler.