Mipmap sharpening is a life saver, especially for whatever texture has your opacity mask, as well as the Opacity Clip strength in the material itself. It should default to 0.333, even dropping it down to 0.3 can improve sharpness. Definitely check your scalability like MostHost suggested though, since if you have any frame drops for a period of time, the editor will automatically drop scalability if you don’t catch the popup. Epic is the better option while you work.
Also I do this a lot for stills, and if you’re developing a game it might not be the best option given that it can increase ghosting, but reducing the number of samples for TAA can improve sharpness. Typing “TemporalAA.Samples” in the console should bring it up and it defaults to 8 on Epic, try anything down to 2.