The best way to avoid double-counting is to use your CRM as the single source of truth and match leads across LSA and Google Ads using details like phone number, email, name, and lead date.
For example, if someone first calls through LSA and later submits a Google Ads form, you should treat that as one customer rather than two. Track the original lead source separately from later marketing interactions, then measure which leads become qualified, booked, and paying customers.
This helps you distinguish between where a customer first found you and which channels they interacted with before converting, so your LSA and Google Ads results are not overstated.