Can I change the block's news titles color?

Hi,

If you mean the block title, the background color and text color can be customized for each block as you like, by editing the page with the composer
– https://www.screencast.com/t/fio3VpC2gw2
If you mean the post titles in these blocks, you could use a code like this to change the text color just for them
– https://www.screencast.com/t/QoLbKm0cIL
This is the code used, it must be entered in Theme panel->Custom CSS if you will use it

.td_block_3 h3 > a,
.td_block_12 h3 > a {
color: yellow;
}

Thanks