You are asking how to be in business. According to Warren BuffetPeter Drucker, a business needs two things, marketing and innovation.
Marketing is what we do to identify who to sell to, what to sell to them, and at what price point. You are finding out that marketing is a lot of work. Exactly. That is why businesses spend so much money on marketing.
In my experience, what worked in marketing last year does not work this year. Marketing is not a "linear" process where we do X and get Y result. It is where we do X, Y, and Z and a customer finds us via B. It is a whole process that may or may not work.
In my experience, marketing has to fit who you are. Trying to do something that someone else does may or may not work for you. Yes, there are a lot of different techniques out there that someone is using to get customers. But, that does not mean that those techniques will work for you. It takes time and experimentation to find what works for you.
In my experience, a good customer is one that A. knows they have a problem, B. has the assets to spend to fix that problem, and C. has the willingness to spend to fix that problem. There are many people with problems who are not willing to spend. One way to test that is to ask for a down payment. People get a whole lot more honest about their willingness to pay the moment I ask for money.
You talk about wanting to spend the time on doing the work instead of this marketing stuff. Being in business means doing this marketing stuff. Often, a business will spend 25-30% of their time and assets on marketing and perhaps less than 40% actually doing the work. A service business needs to mark up the cost of providing the service by 2.5 to 3 times in order to stay in business.
Edit: corrected attribution.