So where are people buying monero, if P2P bitcoin orderbooks are already so dry XMR can't be too liquid either? I did a check and majority of XMR volume comes form CEX, primary KuCoin And if it were banned from all CEXs where's the demand and liquidity going to come from?

From where it belongs, in P2P DEX's. I don't remember the last time i bought something in a CEX.. Only dumb people use CEX's

P2P via Bisq (80% of trading volume is XMR) or Haveno/RetoSwap a Monero based P2P market. KuCoin the last remaining CEX, that has not fully delisted so far. Atomic swaps for BTC Or one of hundred instant exchanges like Changenow