Never accept friends if you don’t know them it’s very easy to say no and delete Choose your own friends No one knows what reasons people have Maybe they have a mutual friend but unless you want them to see what you and your real friends write just delete.... simples
Over the years I have had a couple of really weird friend requests from people I don't know, seemingly from abroad. I delete the friend request rather than just ignore it.
I have noticed at work that when someone new comes, after a couple of weeks they are FB friends with lots of people in the office. I ignore their request.
For me FB is quite private so my FB friends are those I really know and see in real life, and some long distance family. There are a very few friends I have never met, but we met on a private support forum and had much in common at one time, with what our children were doing.
Also be aware of possible scams when someone seems to have been hacked. I had a Friend request from my BIL, but although the name was the same, it did not have his picture, just a silhouette. I deleted it. I was already friends with him anyway.
If I receive a FB friend request, I use Google images to do a reverse look-up of the profile picture. Sometimes (often?) the image has been lifted from the internet to decorate a fake FB profile. In such cases, I report them to FB as fraud.