010101 screaming frog, but it will not work for flarum i guess.
we do have broken activities posts: when a post is split from one discussion and the newly created discussion merged into another discussion the activity link which was created in the first discussion may not work because the split discussion was no longer exists, we need a tool to fix those links but its hard in flarum to check every single post for broken links, maybe a flarum extension can find broken links?
edit:
the screaming frog desktop software will do the job, once you give sitemap it will crawl all pages. we also have Alexa pro, they do provide SEO audits but they only provide for premium users (i use disposable cards to enjoy free trials)
in the case of flarum maybe we can use embed links to load all posts? idk
