Three issues I am trying to solve without replacing the flagstone or major project.

1. Front Patio flagstone is separating in several areas due to what appears to be settling. The area next to my driveway is about an inch thick. Is there a caulking or concrete I can use to fill in the gap preventing/slowdown further seperation.

2. Front Patio Flagstone is cracking (1/4 in. to 1/2 in) on the steps. Same questions above, is there a caulking or concrete i can use to fill in the gaps?

3. Rear Patio Flagstone is shifting and corners on several flagstone pavers is pushing up or going down. There is no concrete underneath, just sand and rock. It appears it originally had some type of caulking. What kind of caulking would it be used? What type of sand should i put under the flagstone to level it?

The house is 10 years old. If there is a video you recommend, please let me know.

Just trying to do the upkeep.

Thank you!