how difficult is it to achieve and how reliable will the method be?

Most importantly, I'd also like to know how to validate data for various fields within Word (e.g. date of birth cannot be >70 years old, salary <$20,000, each employment period cannot overlap with one another for different roles), and then populate these fields in Excel for further analysis next time.

In addition (but off-topic), It will also be a bonus if there's a more secure method of storing sensitive information other than Google forms, especially for job applications (without resorting to enterprise-level solutions).

I look forward to hearing from you soon. Thanks!