If you buy crypto currencies in one country and then travel to another country, as long as I have the passphrase and private key on paper, hidden in mulptiple places and the crypto on an online exchange, no kyc, p2p bought, non custodial and bought on a clean laptop, can I delete the website from by laptop, including the online wallet, and then sign in again to that exchange after travelling.
You are mixing many things up, paper wallets have nothing to do with exchange accounts that usually need your email address and password, but you don't have any control of coins in your account.
Access to your exchange account should be possible from anywhere in the world if you have your login details unless some country is in some restricted region,
but they can always lock your account and freeze your coins or withdrawals like we see happening in Binance and other exchanges.
I have heard, dont know if it is true, but better safe than sorry, that they now have devices to scan your smartphone and laptop to see what is on it. I would not be surprised if they do that now, the governments of the world are becoming very anti crypto currency, especially for privacy coins.
There is no special device that can scan your smartphone and laptop if they are encrypted and protected with strong passwords, but if they want governments can always extort and blackmail you to give them access or go to jail.
Backdoors for devices are also possible but why should they waste time on this when they can break people much easier with old fashioned mafia way, and they are also working on bounties for cracking hardware wallets.