How to merge data? The Mac did not boot, installed the OS from external to external, the data is visible, but does not copy. Error 36?

Question

macOS

Hello! All I need is to dump some data from the hard drive. I see them, read them, but I can't upload them either to the external or to the Internet. gives error 36 (solutions to this problem found on the Internet do not help) only very small files, up to 10 mb, can be copied.
and now the backstory.
the poppy didn’t boot (the circle is crossed out, plus the folder with a question mark), it didn’t show any errors on the disk, so I decided to reinstall it, but it didn’t work out. an older version of the maverick was offered for reinstallation, and the captain stood. as a result, I made a bootable flash drive and installed OS captain from it, but not on a disk, but on an external flash drive (32GB), then the poppy booted up and I went into my disk. I see everything, but I can't bear it. tell me if this is happening because all the work comes from a flash drive and it simply does not have enough power? I understand that by reinstalling the system not on a USB flash drive, but on my own disk, the data will be saved, but still I would like to play it safe ... I will be very happy with the answers!