How to calculate Modulo using a standard calculator for a one time pad encryption
In modular calculations such as this, the divisor (in your case 26) must be at least the size of your character code space. Your code space is 46 characters, so that is not going to work.

Any output of the modular calculation will be less than the divisor, so you will never get 83 for x mod 26, it is not going to happen. For a 46 character code space, 46 is the appropriate divisor.

Also the code space for your message characters is inconsistent, 06 codes to both "6" and "R". 92 will also code the same as 00 mod 46, so your code book values will never work. They must all be unique mod 46.

You have even more problems with your key and ciphertext. There was no modular calculation in generating your ciphertext, or all values would be less than 26. I also have no idea how you got 83+48=105, and 48 is once again outside the code space.