Multiling O Keyboard (https://play.google.com/store/apps/details?id=kl.ime.oh) has swipe. Accuracy is not great and it takes awhile to train but it doesn't have internet permissions at all. It's also highly configurable.
It didn't have the net permission until sometime in 2019, when it started to have it—without any indication as to why, and even the text ‘no internet permission = safer’ remained on the store page.
It seems the permission is again dropped now—but see user reviews for indication that it was indeed once used. For such a personal and important piece of software I for one will prefer an app that doesn't flip-flop on this decision—who's to say that it won't flip again tomorrow? The app is great; it being closed, not so much.