This sounds pretty much like what I've been going through this season. My lessons show that I'm very steep from the transition on the downswing. We have worked hard on ways for me to flatten at the top. In fact, there's a thread here on the topic:
There are times when I feel like I'm making progress on it, but that's typically hitting balls in a very slow motion- or just in a mirror. In slow motion, it still feels somewhat awkward, so I'm missing a key somehow. I think I need to see an instructor physically to get me over this hump. If I get my swing to a moderate speed, the form breaks down and I have near 0 lowpoint control. Fats/thins. Upon review in video, I'm steep again- even when I feel like I'm flattening. Plus my swing gets long again, even when I feel like it is shortened.
I'm just persevering though, as I'm always thinking progress is just around the corner. Until the past couple years, I've never taken lessons (and never improved past a bogey golfer), so I'm determined to just put in the time. I will say that I've never been so keenly aware of the motions involved with a swing. So that's good. Once I can get over this hump, I think I'll be able to have a swing that is more consistent and reliable. I just need to break through this and allow myself to trust letting the club to drop to a flatter position from the top.
For what it's worth, there are a couple folks in that thread above who have conquered this. So it's definitely possible.
When I say I am striking the ball fairly well, it's based on my own personal standard, which is playing the forward tees, shooting in the mid-80s almost every round. I want to break 80. That requires more consistent ball striking, much better approach shots, more birdie opportunities.
Also, my instructor had me working on better shoulder tilt, and according to him, if I get better shoulder tilt, I'm going to need to flatten my swing a little.
AND, as far as I understand it, flattening at the top would bring my right elbow in and enable me to use more body rotation to get more power. PLUS, flattening at the top would get my swing more on plane so I no longer come over the top, and I would strike the ball more squarely.
For me the short game technique is completely different than the long game. With the short game I'm trying to engage the bounce and glide the club more under the ball. I am less concerned with hitting the ball first because the bounce helps out.
With the long game I am making sure the ball is being hit first. With a slightly downward strike.