Use patch to fill the hole. Set the boundary condition to tangent or better.
Then stitch the patch to the surface with the hole.
Sounds reasonable but where is "patch" I can't find anything in Fushion 360 and help is essentially worthless.
Thanks
You may want to watch the tutorial videos in the Learn section. Based on your other posts you are missing some essentials and these videos cover those. There is also written documentation in the Learn setion.