Q.How to get rid of sandburrs or stickers in my yard?
It’s grass that has 3 or more stickers on each stem and there is more each year.

I feel your pain. Literally. I live in Florida, and I've always called them "devil plants." The best way I've found to defeat them is to dig them up, put them in a plastic bag, and throw into the garbage. It takes awhile, but eventually you beat them back. Here's an article on some other methods: https://www.gardeningknowhow.com/special/organic/homemade-pet-friendly-weed-killer.htm