what about all the components and sensors

Apple has bought startups with various technologies like Anobit, that developed advanced flash memory controllers, and have funded development efforts by partners. For example Apple worked hand in glove with Sharp to develop the tech for their 5K display panels. They also now have their own cellular chip designs in some models, in their quest for independence from Qualcomm. That’s all from memory, I’m sure there are many more examples.

so they didnt design all the components and sensors then

Were they ARM investors at the time they needed CPU for Newton? Was that before or after e.g. iPaq PDA-s? And latter - was it that it looked that Apple maybe in danger of going under, and then they sold their ARM stake and got a cash injection that way?

I remember iPaq PDA fondly. Wrote a demo to select a song from a playlist with few thousand author-album-song with voice query. The WiFi add-on was a big plastic "sleeve", that the iPaq slid into, not the other way around. Could run the ASR engine for about whole 10 mins before it drained the battery flat, haha. :-)

IIRC Apple originally invested in ARM during the development of the Newton. The original Newtons used ARM 610 CPUs. I don't know exactly when they sold their ARM stake but they kept their architecture license.

The Newton was long before the iPaq, the MessagePad was released in 1993.

On selling of the ARM stake - asked ChatGPT:

Q> And latter - was it that it looked that Apple maybe in danger of going under, and then they sold their ARM stake and got a cash injection that way?

A> And yes. In the late-1990s turnaround, Apple sold down its ARM stake in multiple tranches after ARM’s 1998 IPO, realizing hundreds of millions of dollars that helped shore up finances (alongside the well-known $150 million Microsoft deal in Aug 1997).