Will redesigning my website hurt my Google rankings?
It can, badly, if pages that rank get deleted or their addresses change without redirects, and this is the most expensive mistake in website projects because it is invisible on launch day. Done properly, a redesign should help rankings, because the site gets faster and the content gets better.
The longer answer
In practice.
How rankings actually get lost
Google ranks pages, not sites. Delete the quietly-performing service page, or
move it without a redirect, and its rankings die with it; the phone stops ringing
six weeks later and nobody connects the two events.
The protective method
Audit what earns traffic before touching anything, map every old address to
its new home, keep or improve the content doing the earning, and watch search
traffic after launch so surprises get caught in days. The full method is at
website rebuilds.
The upside done right
A faster site with clearer pages on the same addresses usually climbs. The
redesigns that end in tears skipped the audit, not the design.
Same rabbit hole