Hide and disable expanding all columns and making rows expandable individually

[Ryota201]

Hi, any solution where I can set howExpandColumn to false which will remove the collapse column and the "collapse all" functionality with it and then add the indicating arrows with CSS and have it work?

Screenshots
Tried doing this in some of the comments on other questions, it worked, but only it visually hides the column headers but if you click on it it still toggles the 2 rows.

If you could help me please, I urgently need this to work, thank you very much.