From my impression and I stress that this is only my impression, Germans on the whole are happy with a unified Germany. If we crudely split the country along GDR/DDR lines then there is a sort of underlying resentment, that's not quite the right word but it will have to do, that the GDR has had to pay for the updating* of the DDR, whilst the DDR feel they were ignored by the GDR in that no major companies moved or created jobs in great numbers in the old east.
I know people who still refer to the Ossies, so that discrimination is still there. Ossies along with all other eastern Europeans are feckless lazy criminals, when actually they've been ignored by the affluent West. It's going to take a lot of juggling and diplomacy to make it fly, and I for one wouldn't want that job. (https://www.theguardian.com/commentisfree/2025/mar/04/jd-vance-bullying-ukraine-hillbilly-elegy-eastern-europe 7th Paragraph onward specifically)
*The Solidaritätzuschlag, the solidarity tax is still being taken to cover that cost, though it has been dipped into for Desert Storm and other bits n bobs. It used to be 7.5%, is now 5.5% and only applies if you earn more than 20K I think.