Q.weeds taking over creeping thyme
I recently planted my backyard in creeping thyme. We tilled up the grass, applied mulch, and planted the thyme seedlings about 10 inches apart. Now I have the grass/weeds growing in faster than the thyme. I have applied Roundup to some of the weeds but I really don’t like to use it and I am afraid of killing my plants. Is there something I can use now? I know that pulling the weeds is the best way, but this is a large area to cover inches apart.

Here is an article on 'Killing Weeds Without Harming Nearby Plants' that will help alleviate your concerns of killing your other plants by giving you different methods of applying Roundup:
http://www.bayeradvanced.com/articles/how-to-kill-weeds-without-harming-nearby-plants
If you would like to explore more organic methods of weed control, here is an article that will interest you:
https://www.gardeningknowhow.com/special/organic/homemade-pet-friendly-weed-killer.htm