Oh wow I didn't know ABB had a Lemmy community. I recently started using it myself. I don't know everything but here is what I do know:

• If your computer is reachable on the correct port, you have done everything right for maximizing uploads.
• Doing so is not entirely necessary because not having that set up correctly at worst means that other users without the QBT port being publicly accessible cannot download from you. I don't know what percentage of users that affects, but I'm on a private tracker also and they claim the percentage is 30% in that community. Not the end of the world.
• Not certain what you mean about not having a public IP. My understanding is you cannot use the Internet without one. The only question here is if your computer seeding torrents can be reached at it. You mentioned setting up port forwarding on your router. If that was done correctly then you are publicly accessible that way via that port. I know there are tests for this online. You could probably search for "torrent direct connection test" and find one.
• It doesn't matter at all that your IP is dynamic.
• I recently also started seeding torrents intentionally. I don't see a lot of uploading either. I had similar questions to you also but other users assured me of the previous things I've written here regarding how this works. I am paranoid about ISP issues or law enforcement so I only allow qbittorrent a connection via my vpn. My VPN does not allow port forwarding, so I'm also limited slightly in that others in the same boat cannot download from me, since my QBT port is not reachable from public.
• It may not feel like we are doing much when you look at how much is uploaded, but I think that's largely a function of there being lots of seeders out there. Every little bit helps! I've seen my total uploads grow a lot over the past few weeks, but yeah it's not huge still.

Hope any of this helps!