Assuming the SM doesn’t have extra spending authority at every AGM you authorize a admin fund budget for the next year. Each line item is what you are authorizing the SM to spend on that item. eg budget $4,000 SM can spend up to $4,000 on insurance.
All spending not budgeted for in the admin has to be authorized by the EC or OR on a vote (can be postal or email if all members approve).
EC or OC can grant members authority to approve spending up to a particular limit (you can impose conditions such as all spending so authorized has to be notified to EC or OC before spending occurs).
In most strata situations the biggest mistake owners make is to assume the SM is a manager as in effect they just administer the Strata on behalf of the owners and have very little power (unless given it by the owners).