Yes you can buy coin from exchange without doing kyc, but if you want to use P2P in the exchange you don't have choice than to submit your kyc. If you are playing to be buying coin in an exchange and you don't want to submit your kyc then I will recommend you make use of kucoin, kucoin exchange those not make it mandatory for users to complete their kyc but if you want use their kyc they have know the user to have scam. Also you can use decentralized exchange like pancake and Uniswap they don't require kyc.
Not all P2P platforms are no KYC, Binance P2P is the example of P2P platform that would ask KYC.
You're wrong to suggest Pancakeswap and Uniswap as the decentralized exchange to buy Bitcoin, there's no way you can buy Bitcoin using Pancakeswap and Uniswap since they're only use ETH and BSC chain. You're only can bought fake Bitcoin e.g. BTCB (Fake Bitcoin run in BSC chain) and WBTC (Fake Bitcoin run in various chain). It's not even a decentralized exchange, but a swap exchange.
The only truly decentralized exchange is only Bisq and it's not good to use Kucoin as been stated by @o_e_l_e_o above.