If possible, don't mix daily usage and cryptocurrency usage since it will harm your privacy and security. So, better to have one phone for daily and another one for cryptocurrency.

There's no such dex wallet, instead non custodial/self custodial wallet. Those wallets aren't secure, if you want to use multi cryptocurrency wallet, use Unstoppable wallet.

And there's no such cex wallet, instead centralized exchange.

I don't think you need to have more tools, having more applications that installed in your device means the more chance or vulnerability you could get hacked.