What bidding models do you find most helpful in digial advertising?

Here are some models I've tried so far. - **target roas: Cold start conversion speed is fast, ROI stability is higher during the running volume stage, roi achievement (absolute value) is better, overall activation cost and single activation revenue are relatively better. - **max conversion: The spending speed is faster; the ROI stability is high but the ROI achievement (absolute value) is poor; the overall activation cost is high - **target cpa: has the fastest cold start conversion speed, but the ROI in the running volume stage fluctuates greatly. Although the activation cost is low, the single activation income is also relatively low