require 'package vs with-eval-after-load 'package

Question

(require 'eglot)
(do-something)

There's another..

(with-eval-after-load 'eglot
  (do-something)
)

They seem to do the same, are there any difference?

Answer 1

Read their descriptions. Not at all the same.

with-eval-after-load doesn't load its first argument; require does.

Even if the require fails in your scenario, (do-something) is invoked. In the other case it's not invoked unless eglot has been successfully loaded.