Adjusting training plan based on recovery metrics? HRV, Training Readiness, Recovery Time etc

From a research/scientific view, ignore all of it. There are no studies that show any correlation/predictive relationship with any of that data. There is a recent TR podcast on that.

You will likely get some anecdotal responses from people who have personal experience. But it will all be N=1.

IMO, using feel and perceived rate of exertion (PRE) is a better indicator of when I need to take a rest and focus on recovery.