Set up Google Tags, Link to Google Ads and Analytics

I need Google tags, triggers, and variables set up in google tag manager which I then need to link with our existing google analytics and google ads. At the moment my google ads aren't correctly recording conversions so I'm missing out on important data. I need to know everything about the visitors who visit our website and make purchases. We have 15 seperate products and other web pages that I want to track. At the moment I am only seeing who is landing on a certain page, this is obviously no good as I need to know what the purchase rate is from the ad as well. Please note I do NOT want to use GA4 due to integration issues with a platform we use. I want to stick with our universal analytics. I need this job completed urgently within 24 hours and I only want a person who has proven experience of doing this.