W10 - ROI & Optimizing Ad Performance

So far it looks like my ads are doing well. According to Google Ads I get quite a few clicks, which is awesome, and they're all within my niche. It also shows me which things people are most interested in, my most clicked keywords are "cheap decorating" and others similar to that. So that tells me I need to do more cheap decorating projects. Though I'm also seeing that people don't stay on my site very long, but Analytics is being funky so I don't even know if that's accurate. Its super frustrating, especially since Google Ads says I get a lot of clicks, and then Google Analytics says I get almost no users on my site. Apparently my site tag wasn't even set up, which is annoying because I definitely did set it up, and it was reporting for a while. I don't know what I'm doing wrong, I've reached out to Google for help and they are very unhelpful. I don't really know where else to go for help.