In your description you mention 2 LTN bugs:

• Connections are lost in some cases
  Are you referring to the bug where destroyed stops didn't restore circuit connections? That was fixed in1.17.1.
  Otherwise please open a bug report on GitHub.

• Supports multi-cargo delivery, but due to bugs it is impossible to fully use it
  Again please let me know in a GitHub bug report.

Thank you for your message.

1. I will try.
2. The main problem was that the LTN outputs the contents of the manipulators to the output port, which fell into the cars when the train arrived. I think this is due to the fact that the contents of the manipulators first fall, and then the train state event is called. This is in terms of bugs.

In any case, I made such an alternative that I myself am much more pleasant to play and will develop it. At the same time, I will be glad to share experience.

I remembered what point 1 was about. Circuit wires are not restored when UNDO-ing.

Thanks for elaborating on those bugs.

1) Undo is tricky with multiple entities. I'll see if if i can make it work but no promises.
Edit: not possible with current API https://forums.factorio.com/viewtopic.php?f=28&t=70393

2) Going with Wube's definition here: "working as intended so not a bug". ;)
Adding a scripted workaround for inserters placing items into trains before they reach the stop would add a lot of overhead. 2 combinators are all a station design needs to be smart enough to never overload a train and get inserters into that state in the first place, so I see no reason to add a such a workaround.

Would be nice if you where to change your description to make those more clear. Feel free to refer to LTN Manual - Known Issues.