Not OP, but have done two large site UX overhauls in recent history, and my team/company takes accessibility _very_ seriously. The biggest pain point for me ha

Not OP, but have done two large site UX overhauls in recent history, and my team/company takes accessibility _very_ seriously. The biggest pain point for me has been the lack of a "Ground Truth" static-analysis-esque tool. We're provided some accessibility-issue-highlighting tooling, and there are some open source as well, but it's very common to get a11y tickets where the tool won't pick up the underlying issue, or will say "there's an issue" but not what the correct threshold is for fixing it (e.g. border contrast/density) so there's a bit of trial and error in there too. If we had something similar to the "green squiggles" in IDEs, with, in my perfect world, the "right click->see suggestions ->auto-fix" flow that I can now get in code, addressing these issues would be SIGNIFICANTLY similar. This is only one facet however, although it brushes against other issues in this space (inconsistent behavior of screen readers, occasionally not having sufficient specialized hardware to even test the scenario fully, often having to "negotiate" accessibility fixes with the designers who gave the original layouts, etc.) Also, a final thing that I'm always curious is "just me" or not, but tab-ordering-fixes have seemed far more painful to handle (in dynamic/scalable layout scenarios) than I would have thought going in. The two options I know of for dealing with it are "assign the order" and "adjust your HTML/Z" layout, and the former is a very blunt hammer while the latter sometimes seems to be at odds with other requirements of the layout. (but this could very well be my naivete in frontend, thus this ramble)