Can not drag'n move the tracks without tempo issues

I’m using Cubase 10 Elements.
I have projects with midi and wavs - drums was programmed in Guitar Pro, and I recorded guitars in wav.
I was about to put some intro before the tracks, so I selected all of them and dragged backward and it totally messed up the tempo. The beginning of the song is 120 bpm, than it changes to 90 bmp. If I move back the tracks, the wavs remain the same, but the midi track goes insane - where the songs changes from 120 so 90, it feels the 90 became 180. Also some of the wavs goes out of tempo as well - it just became pure chaos.
I tried all bars-seconds, timebases etc option with no results - the tracks can not be moved into a new position from the original, otherwise it messes up the tempos.

Hi and welcome to the florin,

Use the Insert Silence function, please.

Did you try programming a tempo track.

Thanx everyone, but it makes no sense to me, so I gave up - spent an entire day reading and watching, but found nothing.

A change to the project beginning is another possibility…

You have to make sure your tempo change is moving together with your MIDI data.