You may check https://www.appeon.com/developers/roadmap (under "PDF Builder) for what is already planned to add for PDF Builder in 2022 R2. Regarding the features you mentioned (the TOC and other links), there are not in the plan yet, but I can add them into the enhancement request list for the engineering team to consider.
It is a beta feature in 2022, and in R2 it will be officially supported. But I strongly recommend to thoroughly test it now because customer input will drive what R2 will be. Please report any feature enhancements and bugs. Thanks!