Is the primary reason you're wanting to disable Shopify Payments due to the payout schedule, or is there another reason? Payouts are based on your region, however; I'm afraid payouts can not be sped up. Typically, payouts will arrive in your bank account within 4 business days. More information on payouts can be found here.
If Shopify Payments isn't the right fit for you, then you can disable it by going to Settings/Payment Providers, then click "manage," scroll to the bottom of the page, and select deactivate. Doing so will not pause your pending payouts. Anything owed to you will be paid out to you on your regular payout schedule. That said, deactivating Shopify Payments will mean your account will be subject to transaction fees.
Transactions fee range from 0.5%-2% per order as per your plan. These fees are paid alongside your Shopify subscription, or when your accounts threshold is hit; whichever comes first. Transaction fees are on top of what you'll pay to Paypal.
Go to Settings/Payment Providers, click "Manage" for Shopify Payments, then scroll down to the bottom of the page and select "Deactivate Shopify Payments" - Once done, Paypal should be the only provider you have enabled.