Can't make bar bigger, can't paste music, in open meter with bar lines

I’m working on a rhythmically complex piece with an open meter, but with bar lines so that it looks organized. I would like to insert a note into a bar, making that bar bigger, however I can’t find a way to do that.
With note input it will enter the note but delete note(s) for the value of the new note. With Insert mode it will move over all the notes of the score, but the bar lines don’t shift with them, thus manually you have to move all subsequent bar lines.

Because I use bar lines (in an open meter), Dorico does show bar numbers. Thus I’d think it would be possible to insert a bar using the Insert Bars function. However, from what I have read elsewhere on this forum, it’s not possible to insert a bar using the Insert Bars function. You can insert a note value, however than I encounter the same problem as above. If I, for example, enter a whole note with insert mode, all subsequent notes move over and the bar lines don’t move with them.

I hope I’m missing something…

Activate insert mode, select the first note in the bar you want to lengthen and create a regular time signature of the desired length of the bar. Dorico adds empty space, i.e. rests to the bar. You can delete the newly created time signature right away and the bar will be in open meter as before, but longer.

If I do the above, yes the bar gets longer, but if I then insert a note, still all the subsequent notes of the score shift to the right without the bar lines moving with them.

Yes. Turn off insert mode afterwards! I probably should have mentioned that.

Yes, I assumed and did that the first time, but in note input mode it then still overrides the notes within the bar again.
In addition, you can still have space at the end of the bar which you may not want (for example a 1/256th rest). I found a way to shorten a bar by 1/256th, to create a bar line before that rest, then delete that small bar after the created bar line.
However, I still can’t just insert a couple of bars containing notes. I guess I could change the meter of a bar to 20/1 to create space, then paste notes. The problem is that b/c I created a meter it will then change the beaming within that bar. In addition, even though I have tried suggestions from elsewhere on the forum, Dorico doesn’t copy the bar lines even if I select them with Ctrl in addition to the notes.

For the insert problem I had a workaround:
-copy the beginning till the point where I want to insert something, to flow 2.
-then insert or add whatever I want to that last bar.
-then paste the rest of flow 1 to flow 2. However, then I get the problem that the bar lines don’t copy.