iPhone keeps disconnecting while restoring it on my MacBook

Hi All,

Yesterday my iPhone has frozen and stuck with the apple icon flashing on the screen. I tried hard resets, but nothing works. My iPhone is showing me information to restore it by my computer.

I plugged it to my MacBook to upload iPhone's software, but firstly I needed to upload my mac's one.

I got the newest macOS Bur 11.01 version.

Here, when iPhone appears in the Finder I click on upload - computer starts downloading a software (it is saying it will take around 20hours for 5gb, isn't crazy?)

Then it stops because my iPhone disconnects after about 15min and the screen gets back to the apple icon flashing.

So I gave up, reset it, found in Finder and clicked RESTORE, but it does the same action as if I click UPDATE. It disappears after about 15min.

Please, can you help me with it?

How can I restore it? How long should it take? If it disappears from finder - does the downloading stop?