The honest bit
Most practitioner burnout is a method problem wearing a self-care costume.
The standard advice is boundaries, supervision, and better self-care. Useful, and it treats the symptom. If your clients are moving slowly, you carry that weight session after session, and no amount of rest fixes the thing generating it.
The pieces here work both ends. Why clients stall and what is actually happening when they do. Why self-healing stops being optional once you do this work full time. And what it takes to build a practice that is still there in five years.
Faster client progress is a wellbeing intervention for the practitioner, not just the client.