https://wccftech.com/downgrade-watchos-5-gm/

In case you’re wondering whether or not you can downgrade watchOS 5 GM back to watchOS 4 on Apple Watch, we’ll try to answer that question.

It’s an age old question everyone tends to ask whenever a new watchOS update becomes available. In case you have the question in mind: can I downgrade watchOS 5 GM back to watchOS 4? We will answer it in the simplest manner possible.