@ikoz I use the Label component somewhere else in the app and the scaling problem persists. The text is still very large on TV.
@kugiigi I've used units.gu() before, but didn't know or forgot the meaning of it. This maybe a good hint, i will try this. Thank you.
As for the header i've found another solution:
Set font.pointSize to hdrrec.height/3, this way the relation stays the same. Maybe i will use this relation thing for other texts the problem still persists, because Text components for which I didn't set a size has no scaling problem. E.g. setting font.pointSize to txt1.font.pointSize*2 or i will try with the grid units like mentioned above.
I will write again in the event of further problems.