Sorry, I didn’t see your posts here until now.
If you want to get a specific user’s attention, you can mention them with the @ sign (like this: @aicreator), though I recommend not doing it too often, because a lot of emails might annoy some people.
If the user has browser notifications turned on, mentioning their name like that will also create a pop-up on their computer or phone. Live notifications are controlled here. (See also this post on how to “install” the forum on your phone — it’s called a “progressive web app”.)
If a post hasn’t received a reply you can bump it by posting a comment on it. I wouldn’t recommend doing it very often, but sometimes it can get a discussion started.
You can also subscribe to specific users in your preferences. (Users can also be “ignored” there if anyone doesn’t want notifications from specific users.) If you click through all of the settings there, you might find a few other interesting ones. 