I'm not an expert or trainer, but you look to have a similar issue to me, which I am working on.
That is we have a lot of tension in the neck and shoulders which is lifting the front end up.
I have been swimming with the focal points of relaxing them both for two weeks now and it is better but still not quite in the muscle memory. But I can feel the air on my trunks more regularly now, which hopefully means I am more horizontal.
Also, relaxed forearm in the recovery is something else I try and focus on. I think we might be the same there as well.
You will probably get better advice than mine on this forum.
Hope this helps.