I am trying to change the way I used to run ads, as the previous method was not profitable for me. I was not following a plan- but essentially I was increasing daily budget with tim. But I qwas also sometimes doing something randomnly- like not checking if the campaign is optimized and just changing the budget.
But I want to follow a pattern now.

The thing s I was running google shopping ads also and for them I started with a good daily budget and I started seeing that my cpc started decreasing. It became 1/3 after 30- 35 days. I thought it is a good idea to decrease the budget now, and so I halved the budget . Now my cpc is the same that is the optimized cost ie 1/3 that I achieved initially in 30-35 days, but it feels that the audience is not buying ffrom the website or adding to cart. I don’t even get my daily budget spent daily. Only about half or about 70-80% daily budget is spent. I am getting more than enough clicks daily , but it is not quality clicks. So I am not clear if this was a good idea or not.

I am not sure if things for the video aads like they do for shopping ads. Can somebody advise mw what process to follow to optimize the daily budget and get good sales.
Should I start with large daily budget and decrease it as my cpc decrease?Or should I start small and increase daily budget as things optimize ?