Yes, all such problems reported (bad sectors, weak sectors, data communication problems) alone can cause degraded performance (too) - so when multiple issues detected, there is high chance for slower operation. But the problem is not (only) the degraded performance.
In theory, the detected and reported bad sectors should no longer cause problems - but considering that the drive has very low Health and high number of bad sectors we can expect even bigger problems: data corruption / data loss (unreadable files/folders and so), un-bootable system, freezes/hangs or just major decrease of performance. If you did not yet encounter any of these, you're so lucky.... Most hard disks with so low Health % produces the issues (and sometimes fails completely) and can't be safely used for storage.
In theory, these "bad sectors" detected by the hard disk S.M.A.R.T. and thus reported in the text description are no longer used by the hard disk: they are already reallocated.
It means that a spare area is used for all reads and writes targeting those bad sectors, instead of the original sectors. This spare area is originally reserved, so the bad sectors (and the health decrease in general) does not affect the usable capacity. So any reads, writes (and disk tests, even the tests in Hard Disk Sentinel) do not access those bad sectors, but tests the remaining data area and the spare area instead of the bad sectors.
This is good, as this way you can be sure that the original (bad) area does not contain important data and can't risk data loss.
So alone the bad sectors can never cause problems, because that problematic area is never used any more. This is why manufacturers allow more or less bad sectors.
However, it is important to know that the above mentiones sector-reallocations are not always complete error-free (can result damaged/lost data) and also during that, the hard disk drive may not responding, causing that the system "freezes" for shorter/longer periods. In many cases, the system may disconnect the drive which can result in unwanted reboot / BSOD or complete freeze.
Some bad sectors can be acceptable - but in case of 1000's (or even 10000's) of bad sectors we can expect more and more due to physical damages, so it is expected to see the above mentioned problems much sooner/frequently.
Plus the mentioned spare area can become full very quickly (it is very small compared to the total capacity of the hard disk drive) so then further reallocations are no longer possible.
For more information about such bad sectors and generally tests to be done in order to reveal and stabilize possible further problems (eg. on sectors which are less frequently used, as there problems can remain hidden for very long time) please check the proper sections of the Frequently Asked Questions page:
https://www.hdsentinel.com/faq.php#health
https://www.hdsentinel.com/faq.php#tests
Without knowing the disk status, hard to say FOR SURE what could cause these problems. Can be physical damage (shock, vibration), electrostatical discharge, power supply, cables/connections, overheat, mechanical wear due to the age, etc.
Personally I'd not expect too much from a hard disk drive with 4% Health: I recommend to backup immediately - and then maybe try some tests (eg. Disk menu -> Surface test -> Reinitialise Disk Surface) in order to attempt to stabilize the issues - and improve the usability of the drive. But it will surely not be 100% perfect again, so I'd not really trust (even for secondary storage).
The 6000+ data transfer errors can be also a problem. Generally yes, when such error detected, the hard disk automatically switches to lower performance and retry the transfer so _in theory_ there are no data corruption - however, we found situations when high number of data transfer errors could also cause data corruption and/or the disk "just" vanished from the system (like if you'd disconnect it) resulting BSOD / freeze or similar.
If you use Report menu -> Send test report to developer option, it is possible to check the complete status and assist - it may give some ideas, thoughts about the hard disk drive.
