Create a character style for the lettering and insert the colour there - then you can change the colour without selecting the text.
Character style for letters within a paragraph - if it's the whole paragraph then choose a paragraph style.
I see other users giving tutorials, that when they select the text appears a background that doesn't affect the color of the text, do you know why they have this behaviour?
Can you point to these tutorials? As you can imagine, I don't watch tutorials