2scents- regarding yitzro Gadol heimenu- The Rebbe taught about Yochanan Kohen Gadol (The one who went off at 80 years- hope I got the name right) that if a tzadik doesn’t keep pushing at his avoda (which is above struggles with actual aveiros in action, speech, thought as mentioned- Tanya yud)
Then he can lose his level and descend all the way down eventually like what happened by Yochanan Kohen Gadol.
Like we learned in school that in life you need to run up the opposite direction escalator- it’s not a ladder- if you’re not going up you’re going down r”l