Moving from "WordPress + WP Engine" to Squarespace: Downtime?

Hi! I'm exploring moving a client from WordPress (powered by WP Engine + Domain Provider (unsure)) to Squarespace. I'm planning to completely redesign their website, so not concerned about copying content over from WordPress.

Does anyone know if there will be downtime moving from WP Engine to Squarespace as a hosting provider? If so, is there a way to set up a redirect link to a maintenance page or something to that effect? How long would the downtime be for?

Any help appreciated!

@SophieByChance Hi! Downtime typically depends on several factors, including DNS propagation time. I did something similar a few months ago (Bluehost hosting + GoDaddy domain), and the downtime was less than 10 minutes. However, it could take up to 48 hours.

First, I finished building the Squarespace site. It was a complete redesign project involving copying content from an existing WordPress site. After building the website on Squarespace, but before pointing the domain to Squarespace, I created a temporary maintenance page on the WordPress site and set up a redirect from the WordPress site's homepage to this maintenance page. Once the propagation was complete, I took down the WordPress site. Obviously, it's important to create a backup of the WordPress site before doing anything else.