OP, please understand that when people say "guest posting," they actually mean many different things.
This is where people get into trouble.
Guest posting to a PBN will be very different from guest posting on a site that has traffic.
There are many advantages and disadvantages to these types of guest posts.
When you pay for your link to appear in a guest post that will be published on a blog in a PBN network, you don't know what you're going to get.
Who knows the actual page authority and SEO value of the page your link will appear on.
The good news with this type of guest posting is it's guaranteed because you shelled out the cash.
Guest posting, on the other hand, at sites with high authority and high traffic is more of a gamble.
While some of these sites ask for money, a lot of them are only interested in their posts.
Are you offering something that their visitors would find interesting or even valuable?
This is one point that many "guest post link-builders" totally miss.
They focus on the process only from their point of view.
They're thinking, "What do I get out of this?"
If you were to flip the script and focus on what your guest posts have to offer the audience of your content, you would probably achieve more success.
Remember, people don't care what you know until they know that you care.
Come into the game seeking to offer value.
How do you do this? Ask the blogger who you want to publish your guest posts what their needs are.
Don't just focus on keywords; focus on the needs of the audience they have.
This could be shocking because it might be a completely unrelated audience.
Do yourself a big favor and focus on how much value you can deliver, and you will be surprised as to the results you can get.