I work pest control and had a couple thoughts for you.

1. Is this on a second floor? If it's first floor it may not be as bad as it seems but seeing winged termites, alates, they may have been there for a hot minute. I would remove the toilet and check the area around the pipe. If you see any mud tubes going under the tiles you will need to remove the rest in the area to see how far they traveled.

Should this be a one story slab house pulling up those tiles will show any cracks in the foundation were they came up from. These cracks and any others would need to be treated along with on outside treatment.

1. Depending on where you live, it would be better to shop around and find a pest control company you feel would do the best job at a reasonable price. I'm in the south east us and it's bugs all year around. We have huge termite issues here and there are a lot of companies to choose from.
   

If you have any questions feel free to DM me.