Respectfully, but this post shows you do not understand genetic genealogy, which is factual science.
1)
the genetic genealogists do not give the police suspects. They build family trees, which takes an enormous amount of research and time. They use factual evidence to build the trees: birth, marital and death records.
2)
The police take the family trees and identify possible suspects, by using age, location etc. The possible suspects are investigated by the police. They gather DNA and the suspect is only arrested and charged after their DNA matches crime scene DNA
3) the DNA is not being “mistreated by being put into many systems”. Again, you have admitted you are not a scientist, so I think you misunderstand. The actual DNA is not put into GEDMatch. The police send the crime scene DNA to a lab, such as Parabon. The DNA is used to create a full DNA profile. The DNA profile is data, not the actual material. This DNA profile file is uploaded to GEDMatch, not actual DNA material.
4) in the GSK case, the coroner in one of the murder victims cases took 2 Rape Kits. The DNA in GSK case to submit for the full DNA profile came from the 2nd rape kit which had not been previously used.
The 2 links: 1) genetic genealogy explained 2) the 2nd rape kit in the GSK Smith murder.
Crime solvers embraced genetic genealogy
How 2 key ideas helped break 'Golden State Killer' case open: Investigator