UXUI Only vs UXUI Adaptive Accessibility Tools in Your Tech Stack

Wanted to get some thoughts on your opinions of saying UXUI solves all problems vs accepting that UXUI will not be perfect and instead including tools in your tech stack that allow quick ways that users can more easily access your product. Asking because I have come across multiple founders solely focused on UXUI as their main means of accessibility and I wonder whether people conflate the means with the ends of accessibility. Examples of such tools include help forums, no code tooltips, WYSIWYG editors for product tours, Loom as a quick comms tool etc. Any thoughts?