First, please let me apologize for my lack of proper vocabulary. 😃

I have a Canon EOS R50 with the stock 18 to 45 lens.

I need a stronger telephoto capability, to take bird pictures, the moon, get that lone oak tree out in a field etc. There are devices that one can place between the lens and the body to <<telephoto more>>, right? Would it be better to get one of these or to buy another whole lens? I am assuming the adapter would be less expensive. Money is a factor. (isn’t it always?)