Remote is making people reevaluate work/life balance in general, some people that aren't getting their preferences matched in this regard are thus leaving.
Huge amounts of liquidity means there is now a lot more money sloshing around in the pockets of startups and public tech companies that raised money in the 2020/2021 equities boom. Tech companies suck at retention based raises (I still have no fucking clue why this is) so there is a large amount of reshuffling happening as people move to take advantage of better wages being offered elsewhere.