OMG you have described us to a tee. We're currently in this and have been for around 2-3 weeks. I cannot wait for her to actually nail it I'm hoping we might get some more smiles again!!
My little one went like this then decided forget crawling and now walks
Mine (1st August) is crawling well now, but this was us around a month ago. I think the frustration is part of their learning and though it's hard to deal with is temporary. To help (when she couldn't get her knees up) we would support her in the crawl position and got siblings to demonstrate crawling. Not convinced it helped, but stopped the grumpiness for a few mins at a time . Once she cracked crawling it was bliss for a few days until she now intruding to stand and gets angry about that lol