there are offices that offer these services offline. if you wanna do it on your own youll need to request a lot of acces to city archives. At least in some countrys, citys keep many infos. including if someone moves there ect.
So if you know where your grandparents used to be born, go there, and maybe you find infos about your grand grandparents. and then its just a game to hunt for infos. See if you can find your anchestors names in unis, or companys or something.
I heard its quite tedious and takes years
Really depends on what you do and value. I use lots of kde software, so kde distros are my go to. then one big diffrence between distros is how they get updated. do you want the latest updates asap on the costs of stability, or do you want an effing never crashing distro but lag behind in updates a few months/years, or a middleground.
These are the two points i considered when i choose.