Hello, all, I have good news for you.
The mw:Editing team held the mw:Talk pages consultation 2019 last year. mw:Talk pages project/replying is the first major tool that they built because of that consultation. It works on wikitext talk pages. (It has no effect on Flow pages.)
Right now, the tool is available at the French, Arabic, Dutch, and Hungarian Wikipedias as a Beta Feature. The Editing team is making a short list of Wikipedias that will get the new 'Reply' tool as a Beta Feature next week. About 8 more Wikipedias will get access to the Reply tool. It will be opt-in. To use the tool, you will have to go to Special:Preferences#mw-prefsection-betafeatures and turn on the tool. If you don't turn it on, nothing will change for you.
The Catalan Wikipedia is currently on their list. I have been using the Reply tool at many wikis, and I love it. However, if, for some reason, you do not want this Wikipedia to get access to this tool next week, then please tell me as soon as possible. Otherwise, I will assume that it's okay.