Thanks! You should probably provide a link to this topic Testing Nested Replies on Meta (or I couldn’t find it).
I specifically registered to write this.
Reply chains are the most painful part of forums. To read all the related replies, you have to constantly click to display/jump to parent/reply replies, making it impossible to see everything at once, and sometimes figuring out who’s replying to which message.
Summary
For example, this post iOS 26 bugs with fixed position elements in Discourse - #7 by awesomerobot When you open it, you can’t immediately see which message it’s replying to (you have to click “Load parent post”), the content of the replies (you have to click “1 Reply v”), or if there are more replies to this post and how many (you have to click “Jump to post”).
I’m a master of compromise 
and I came up with this compromise. The main display is a flat forum, but a post with parent/reply has a BUTTON that opens the ENTIRE chain of related posts in a new window, in a thread/tree view, in which this message will be in focus (for example Testing Nested Replies on Meta - #101 by Ed_S (thanks for the implementation, this is what we need!), but make it so that 10 nested / threaded are displayed without clicks (to do this, make the Topic width wider, now 50% of the screen is empty. As an example, 10 nested fit normally in width forum.opennet.ru - "У меня отжали 2 квартиры в Москве с помощью ЭЦП" (81) ; Полная доказательная база аудита мессенджера MAX / Хабр ), if there are more than 10 nested, then “show more” Opens a new window from this point, but displays the two threads before this message and the eight threads after, etc., to avoid reducing the width. For mobile devices, make the 5 nested.)
This is especially useful in a thread with 1,000 posts when you search for a word, find a post, go to it, and it’s not clear which post the answer was to, and you have to click 10 more times to display the parent/reply link.
You can combine this BUTTON with the number of replies and the thread depth display, so it’s clear that the message is within a larger discussion even before opening it in a new tab.
This combines the advantages of a flat forum (easy reading of the entire thread) and a tree-based forum (the context of a specific reply is visible), without forcing the user to constantly click “go to message” and “show reply” links.
Let’s make forums more convenient than instant messengers and social networks to offer better usability and functionality!