The original ethnicity estimates were a guess based on the surnames and nationalities of the tested of your DNA matches. This was refined but you found a difference between companies and websites due to the differences in populations using those sites. So, it was an 'educated guess' (what we call in the UK a "guestimate" - some truth but not to be trusted.
In 2021 the game has moved forward and your old evaluation has been re-assessed using DNA, against known 'native populations' - they have to have 8 great-grandparents from the same locality to provide any proof of ethnicity to a testing company. These families are then used in comparing your ethnicity with known natives.
You should treat your percentage ethnicity in the same way as a percentage DNA shared with a cousin? If you know it comes from one side of your parentage then it is easier? The more ethincity, the closer the source. Ethnicities of 1 or 2% are way back in your tree? People in America will have more problem with this due to the massive ethnic mixing over 300 years of immigration and the mobility of people too.
Prehistory and Historical Ethnicity
Your haplogroups are parts of DNA that change little over the centuries and thus provide the clues about human migration from eastern africa across the globe. Haplogroups can also determine geographic origins in more recent times, up to and including the time of recorded history.
Some websites will give an idea of how far back it was that say your French, Swedish or Jewish ancestry was introduced in the last couple of hundred years which might help direct your research.
Please note there is a difference between Haplo-groups and Haplo-types. The latter is more specific and is used in maternity & paternity testing. It is used to identify subgroups in genealogy for a given surname.
Seamus Crowe Website2021