Important to remember that European banks play a big role in dollar liquidity intermediation, mostly through subsidiaries and broker-dealers. During the GFC, they received immediate support from the Fed through liquidity swaps. Things could get murky if that support isn't there next time.
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How does this factor into financial stability regulations? Does the EZB, SNB, BoE, etc need to do more auditing and capital reserves?
A global reserve currency is nowhere near as important as it was just a few years ago due to technology and pricing dynamics.
USD will weaken, inflation will runaway, Fed will try to keep up.
In short, tech -> increased market efficiencies -> multipolar reserves if necessary.