The time-accepted remedy among 1911 smiths is to first remove the slide from the frame and insert an empty under the extractor hook and against the breechface to check the extractor fit. The hook "slot" should contact the case extractor rim with very slight force, and most out of box extractors need the slot cut a bit deeper so that the case rim barely touches the bottom of the extractor slot. Ideally, the empty should hang loosely, sorta tilting forward and down. Too much tension, or force of the extractor against the case rim will hold the case firmly against the breechface and cause the vertical ejection what you describe.
In addition, some 1911 smiths also grind away some of the bulge halfway back the extractor, reducing its diameter to allow the extractor to flex more.
A third modification is to gently round the bottom corner edge of the extractor hook and polish the hook face, edge, and slot afterward.
I usually do all three and the empties fall in a pile 18" in diameter about four feet to the right and two or three feet back. I've modified maybe 20 or 24 1911s and clones with the same positive results.
Opening up the ejection port to that of Gold Cup dimensions will help, but not without the above extractor mods first. The port modification downside is needing to refinish the edge of the port where the 1/8" or so of metal was removed from the bottom edge of the port.
Noah