You need to use a better OCR service. You’ll probably need to pay for it to get a good one.
There’s another topic here where I discussed OCR and the exact problems you’re having. I can’t find it at the moment but if I do, I’ll post here. There’s really nothing you can do in Thunkable to improve this problem. You need better OCR.
Edit: Here it is: OCR API and search results don't show expected output - #42 by tatiang