It doesn’t make sense to trigger a Rule by both a changed and an update on the same Item. For example, in this case the Rule will be triggered twice when it changes to ON, once for the change and once for the update, since a change is an update.
To get the behavior you are after I think all you need to do is remove the received update trigger. The Rule will trigger when ever the Item changes to ON and create the Timer. If you turn off the Switch then turn it on while the Timer exists, it will be rescheduled.
In the future, please How to use code fences for posts containing configs, rules, or logs.