Could we have a discussion thread on FlashBots, MEV and gas prices?

Would be grateful if some of the devs or OGs have time to chime in on this, given that gas fees have plunged quite drastically.

1. Is it likely that the reducing gas fees are because arb bots are using FlashBots than PGA to finalise their bids?

2. Is there a long term danger of block rearrangement, network instability or any other attack angle if the use of Flashbots to settle MSV transactions becomes more popular?

3. How would MEV dynamics be after PoS finality? Are there still priority gas auctions, with tx fee paid to validators? So we can use Flashbots after PoS finality too, just that miners are replaced by validators?

4. What is the benefit to miners (eg Sparkpool) in integrating Flashbots? Wouldn't they get the same tx fee even via PGA bots? Surely they aren't using FlashBots purely out of altruism to reduce network congestion

5. Could usdc/dollars and not ETH be used to pay for the Flashbot tx, as it happens off chain? Does the use of a base fee in eip1559 adequately protect against this sort of off-chain agreements?

some of the questions may not be technically correct, please do feel to point out and correct any flaws in the q's themselves