For what it’s worth, I recently travelled to the US from the Middle East (into Houston) and was also concerned about this.

My solution was to delete apps I didn’t want to be searched (e.g. WhatsApp) after having made a cloud backup, then enabling airplane mode.

CBP’s website [1] states:

> Prior to beginning a basic or advanced search, CBP Officers will ensure all data and network connections are disabled

And no, I wasn’t searched (thankfully!)

[1] https://www.cbp.gov/travel/cbp-search-authority/border-searc...