By default the forum currently don't have a notification to notify the users if someone posted in their thread, only users who use telegram bot that know it.
You don't need to use the Telegram bot, you can enable email notifications when someone replies to your own threads or to watched ones. Of course, your email address needs to be an active one.
if it is a case where such discussions in the OP arises in the future can that same thread be reactivated or it will be better to create a new thread?.
Up to you, there's no rule to forbid someone to bump old thread as long as your post is important and necessary, create a new thread is nothing wrong too if you want to discuss about a new thing that differ from the old thread.
If you have something really unique and new to contribute to an old thread, I would be fine to bump it with such a contribution. If you fear to necro-bump a thread, create a new one, give a link to the old thread or particular posts of it and be good.
I'm not such a fan of fragmentation of information about the same topic over various threads, though. It makes searching harder as you get more hits and have to decide where the really good details are buried.
But as always... YMMV!