like of an answer to „How to Merge when you get error "Hint: You have divergent branches and need to specify how to reconcile them."“ :

Not everyone wants Git to do merges. Suppose you have made one or two new commits, which we'll call I and J, and your git fetch from origin brings in two new commits that they made since you started, which we will call K and L. That gives you a set of commits that, if you were to draw them, might look like this:

          I--J   <-- your-branch
         /
...--G--H   <-- main
         K--L   <-- origin/main

You can fast-forward your main to match their origin/main:

          I--J   <-- your-branch
         /
...--G--H
         K--L   <-- main, origin/main