I understand why there are communities who do world building for fun, but it seems overwhelming now. To build an entire world and history from the ground up sounds exhausting. The great advantage of using the real world is that you can drop a vague location of “the city hospital” and people will imagine a real hospital that they have seen before. If you drop a vague “the Uruk-hai”, then nobody has any idea what you mean, and you have to first explain it to them. There is a reason so many fantasy worlds are clearly re-skinned Europe: it gives the author a nice starting point and it gives the reader a shorthand for what things look like, how things work. To write a completely alien society, architecture, language, geography would force you to spend most of the book describing everything. This is fine if this is the whole point of the book, some sci-fi for example. Distracting otherwise. Probably, one can go too far: There was an aspect of the world in this new story that was to be a source of conflict for the protagonist. As soon as I saw an alternative I felt the need to move the story to the real world. After all, the world building was no longer necessary. World building should be in service of the story, no? Well, not only. Also for fun and wonder and novelty. (Apparently I am a sullen man whose thoughts when writing are drawn to dark places free of such things.) You could write a book with similar plot and themes to the lord of the rings in 50s England, but it would be a very different book.
Another options is to set the story in the real world, but in a different time and place. Unfortunately, this opens you to the possibility of making objective mistakes. You can no longer write whatever you wish and declare it so. You need to do extensive research, avoid overlapping with any major historical events without mentioning them. Again, I get the feeling “Well if I’m not using any of these historical events, then why bother?” Well, to gain access to particular mood, a particular set of circumstances that fit with the story, a particular character that fits in this time and place, or who doesn’t fit in an interesting way.
It seems that I am lazy, and should perhaps take the easiest choice: to set the story where I live, in the present day. I know this setting well, after all. To ensure no mistakes, my characters would only do jobs I’ve done personally, and have the same background as myself. Maybe an autobiography would be best.
As a middle-ground, I do quite like the idea of creating slightly fictional settings, like the town of Midsomer, or Hardy’s Wessex: based on a real time and place, but the veneer of fiction you put on top allows you to diverge from reality where necessary.