I doubt this is the fault of the app developer; I suspect the issue is with Apple. I find this works well for pages viewed in Chrome but I'm running current versons of Big Sur and Safari annd Chrome on a MacBook Pro and Safari doesn't, as Chrome does, display correctly the URLs I've generated with Link Text Fragment display. When Chrome loads the URL, the page jumps to the designated anchor, where the text is highlighted). Paste the same URL in Safari and the correct page is displayed from the top. It doesn't jump to the designated anchor, nor is the text highlighted. I'll text it on my iOS devices and the non-Apple devices I keep around for test views and if I have good results, I'll update.