PBNs really worth it?

All donors have TF> 10

PBNs can last for many years and they can get more powerful over time, depending on how well you promote the sites.
you have full control over your own network if you build one yourself, so you can use it for multiple sites.
of course if you just buy a PBN service you wont get the same results as these services are not true PBNs most of the time, unless someone builds a PBN only for you.

making pbn is way low cost. but need to analyze the domains before buying them. you can make enough content for a pbn site with 50$. and setup will cost will be 10-30$. depending on the size or volume of work it need. you can easily get everything back. like old urls that have high quality active backlinks. i have done PBN for my clients. main problem is content making. my client was busy. otherwise i can make 3 PBN site daily. main problem is the time duration. u have to wait 7 days for making each new PBN. google will check them in future. and remember, they will manually check it.