Google assigned a free advisor to me last year. I have been working with their advisors on and off as they constantly disappear and I’m reassigned another one. Each time they tell me they’re assigned to me for the quarter, but that never happens and it can be months before I get reassigned. They’re very helpful when I do receive the support. What should I be doing in place of having an advisor when you don’t have a budget to hire an agency.
Hello MGSG, thank you for your question, a rather interesting one, as I’m surprised you find them helpful.
I have always found them to push for settings changes, or campaigns, or other things that increase costs. Even subtle ones that you may think are ok, but sneakily increase costs. As that is the objectives of a Google Ads Advisor.
I have for 5+ years, stopped listening to them, as I work for clients that want to increase performance, not just costs 
If you plan to learn yourself, or want to do everything yourself, looking at youtube videos and written articles is a good idea. However be careful with guru youtubers that are just full of wishful thinking.
You can start with looking at some of my videos, I have alot to share: https://www.youtube.com/@feedarmy
So keep on reading, learning, testing, failing, and redo the process.
Also go to linkedin, connect with the right people, as they share content as well, but here too be careful, lot’s low quality content is shared as well. I call it fluff, or cloudy content. Lots of info, but just share, what has been shared a thousand times before as well.