While I'm sympathetic to members who'd like to be able to exclude, or at least easily distinguish, recipes that need advance preparation in searches, my experience is that in the actual process of settling on specific recipes, it's pretty easy to avoid them.
Let me encourage EYBers to make liberal use of Bookmarks, which are flexible enough to make up for indexing categories that don't exist. Tagging 'Sheet pan', 'Braise', and other cooking methods of interest can quickly build up a body of knowledge; my growing 'Pressure cook' list has made a real difference to my cooking.
If you frequently do a search that turns up appealing recipes but then are put off by the need for advance prep, bookmark those. That way they're easily available to you in situations where you have the time and motivations to tackle one (like entertaining, or as a skill-building project). Or they'll be easier to spot in a list of recipes when you want to exclude them.