Autocomplete rule to add + 1 day to calculated Probation End Date

Content (required): We have a requirement to add +1 day to calculated Probation End Date in case selected units are Weeks or Months. I've tried to achieve this with autocomplete rules, but keep getting error :

I understand why the error happens, but can't figure out a way to bypass it and achieve the desired result. Is it even possible to get it working with autocomplete rules or should I use something else?

Calculation example:

Hire Date: 01-APR-2023

Probation Period: 3 Months

Calculated Probation End Date: 30-JUN-2023

Desired Probation End Date: 01-JUL-2023

Code Snippet (add any code snippets that support your topic, if applicable):