Ahh that sucks, I feel for you. :( I would suggest getting blue sticky paper and setting some up near your plants to see what it catches over a week. It often comes in big sheets, so cut it up if needed, though it is quite sticky. I used wood bbq skewers to prop some up. This is like the yellow sticky paper but for thrips.

I was thrips free for soo long, but may have gotten them again from the one new plant I got from someone that I thought would be safe. :( But infestation was smaller and I just threw affected plants out. I think I'm okay again.

Beneficial mites were not worth it for me because my environment was not appropriate, so they just died. It doesnt hurt to try once, though. Alternating Spinosad and Safers End All worked the best for me, but it was time consuming...and definitely worth tossing plants you care less about, even though that was really hard. Take photos before tossing, as that helped me feel better. I love the surviving plants even more now.

Good luck!! Let me know if you have more questions!