„Tamto tylko jeden sposób” is grammatically incorrect. I know it may be confusing, but there is more than one „to” in Polish. This „to” (with omitted, but assumed „jest”) is used as an English "This is/That is/It is" and it has no equivalents for different distances.
For "there's only one way" you should use „jest tylko jeden sposób”. As you see, it gets rid of „to” (since we don't want to specify the object) and makes „jest” reappear (because you shouldn't drop both).