If you own coins in a wallet to which you own the private keys then after any chain split you will own coins on both chains, you can keep both or sell both, either way buying now ( and taking coins off exchange) gives you options, buying after a fork, you have to pick which chain and hope you pick the right one, or buy on both chains.
I keep all of my btc on a ledger wallet and only +-20 on kraken it Good like this or to put nothing on kraken ?
I would make sure that you move most of your coins to your ledger wallet by July 30th. Maybe earlier. Who knows if someone is going to deliberately try to clog up the mempool again. Transactions should be brisk on the 31st anyway..