I haven't gone back through this thread lately so it is possible that I have shared some of this information on this thread before.
Relative to the LDS centers in SLC and other places: I was in SLC in 1983, at the main Family History center. I had very little luck there. At that time, Czech records were not available except if you went to what was then called Czechoslovakia and went to the government centers where records are kept. A couple decades ago that changed. Now it seems that Czech genealogy is one of the most popular countries for research on Ancestry. One of the things that has happened is that LDS have a mission for seniors who go to Czechia and photograph the old records. I happen to have a friend whose parents have been there, doing exactly that.
I have also been to a few History Centers in the Denver area, again with little to no luck. All of these are run and worked by volunteers or rather people who are appointed or assigned. I usually know more than the volunteers. I have been sent down rabbit holes that took me to places where my family never lived. So much wasted time!
There are a few things that changed my research.
Czech records became available to the public and are available on line. I know that many records are available online now, not just Czech records.
There are groups for people focusing on particular areas or countries. For me, there are professional Czech genealogists who started and run a Facebook group with thousands of members. There is more than one Czech genealogy group, but there is one that is run by professional Czech genealogists. There are groups for Nebraska Bohemians (Czechs), Chicago Czechs, and more. The group run by professional genealogists has been where I have gotten the best help, but every group has had people give me useful information. People have been willing to go to cemeteries in Nebraska to take photos of headstones, etc. Nebraska Bohemians are proud of their heritage. A man in Chicago drove around to a few places one week, helping a few of us figure out what happened to a relative whose parents had divorced in the 1870's.
I went onto the Czech Facebook group run by professionals and posted a photo of my g grandparents headstone. They happened to have a very nice headstone as he was said to be the first millionaire in their county in Nebraska, running a slaughter house and butcher shop. The headstone lists their place of birth, in Bohemia, now Czechia. Within half an hour, probably less, someone shared my g grandmother's birth record. And since I couldn't read the old script nor the language, they then translated the record for me and gave me information about the additional information on the record.
I have a line in one part of my family that is full of misinformation. A gg uncle was married, lost his wife of almost 20 years and then remarried. His second wife was full of it, lies and other baloney. She never met many of the family, but gave information on death records that was completely untrue. She said that the young daughter by the first wife was hers. She was absolutely not, as noted by photos to compare potential ages. Story is that she paid officials in Chicago to change the girl's official records. She said that Matthew was John's father. He was not. Matthew was John's grandfather. The problem is that more than a century later, there are people in that family who still believe the lies and misinformation and continue to propagate it, in spite of me providing actual record images. "Oh no, these are wrong." Can records be wrong? Of course, but when one man is named repeatedly in records for a family as the father, then someone, almost a century later who never knew them, tries to change the information and the descendants want to say she is right when there is repeated proof that this information is not accurate.
For me, images of the official records are exceedingly important. Someone can say they have done the research, and maybe they have, but where is the proof that what they say is true, or not?
One of my uncles died and my aunt, his sister was providing information for his obituary. She and another uncle tried to call me, but I was gone, left early for work. So they said he was born in X because several of them were. He was not born in X, he was born in Y. His obituary has it wrong now, and in the future, how many will believe what the obituary says? The uncle who tried to call me told me not to say anything to aunt, because she would just stress about it. I didn't say anything, because so what? Obituary was already printed.
Find proof if you think information is wrong. Write letters to get records. Look at official records. Arguing with people doesn't serve anyone.