How to recover lossless MySQL MyISAM tables from files?

Question

MySQL

Good afternoon!
We have damaged disks on the server and partially lost data.
The backup in terms of the database was not the most up-to-date, so it was decided to restore the database from the saved .myd, .myi, .frm files.
Since the tables were MyISAM, the recovery itself is simple. Stop mysql, copy files to directory, start mysql.
As a result, the databases have risen, at first glance everything is fine, but it turned out that some of the records in different tables (within the same database) are missing. CHECK TABLE at the same time does not show any problems, and in general, when working as a whole, no problems are noticed. There are no strange glitches, no corrupted or erroneous records, that is, it looks like everything is in order.
As a result, two questions have arisen:
1. Has the database recovery process been carried out correctly? In theory, there are no difficulties here, copied the files and you're done. But maybe there are nuances?
2. Generally speaking, how could such a situation have come about? Judging by the fact that everything was restored without any errors, we can conclude that these database files were not damaged on the failed disk. But why and where did the records disappear then? Is there anyway to get them somehow? Just in my understanding, if the file was damaged, then nothing would be restored. And then it turns out that several hundred / thousand records just disappeared somewhere. (Total database for 100k+ records)

Answer 1

and so they
tried www.mysql.ru/docs/man/Repair.html