Combining clips using Generative extend / AI

I don't think so.. Your best bet would be a 4 to 8 frames Morph cut, but you said you already tried it.. I'm just replying cause I think that would make a great feature request, something reallyuseful for AI to make.

It could be called Generative Fill or something.. it would be really neat.. I hope it's in the pipelines..

If the camera is static on a tripod - why not use a standard Cross Dissolve? ..to avoid a jump cut.

Not clear if it is an interview but depending if you shot say in 4K and export on 1080 HD - you could zoom in on some shots to create a 'pseudo' B roll shot if the quality is good enough.

Other options/ideas  - use Transition Packs which create overlay on video tracks above across the cuts in the footage to mask an abrupt cut.

I've never seen a perfect 'pixel stitch' from one cut to another

Instead of that, you could cut to B-roll and then cut to the second clip.

What type of clips are they (an interview, etc.)?

Morph Cut?

Not ... really. Although there is a tool to mush over cuts to remove a short bit, but that's pretty finicky to get a cut that blends right. I use it so rarely I forgot what they call it!