to start configure Google Analytics Smart Goals to Google Ads. please follow below notes:-
1- Smart goals are not a configurable or able to customize like normal goals.
2- only one smart goal available per view.
3- Smart goals will take up 1 of the 20 available goal slots (like any other goal).
4- Smart goals are currently only available for website views.
5- Smart goals are not available for views that receive more than 1 million hits per day.
6- Smart goals do not support the view through conversions (vtcs) or cross-device conversions in google ads.
7- Your Google Ads account must have sent at least 500 clicks to the selected Analytics view over the past 30 days before you can set up Smart Goals.