I use PhpStorm by JetBrains and am totally blown away by how powerful it is. It does all of the GP’s list and way more.
1. Heap size is too small and it's GCing a lot without the user realizing. Open IDE VM options and double the -Xmx setting.
2. Using a 4k display on macOS. Try the new JBR17+Metal builds. They aren't shipped yet but switch it to using Metal to render. Makes it a lot faster.
My heap size is already at 3GB, which I feel should be enough for opening a bunch of 5kb text files :/