kakku - here's my method, it's a couple clicks. Once you get the hang of it it's super easy and super surgical.
Say you want to remove 50 measures (or whatever your minute of time is) to the left of your remaining material. Note where your good stuff starts, like say measure 50.
Click on any track. Then click Control A (select all).
Under the Edit menu choose Select By Time. Select a range of 1 to 50. Then choose Delete Special and remove the appropriate options (including events and markers).
Another scenario, let's say you want to repeat an existing chorus. Let's say the first chorus goes from measure 16 to 24.
You can Select All again. Select by Time, select a range of 16 to way out there, like 150 (your whole remaining song).
Then choose Cut Special (including events and markers). Paste Special, paste at measure 24, include events and markers etc.). Now you've opened up an 8 bar blank spot between measure 16 and 24.
Then, Select All again, Select By Time, choose range of 24 to 32. Copy Special (include events/markers etc.). Paste Special at measure 16 (including events/markers).
With that process you've surgically added a repeat of a chorus so you now have two back to back.
The above is a second use case of how routine and precise Select By Time is for editing sections. This can be done with single or multiple tracks, or with Select All, and all of the tracks.