Useless, I started thinking of you just now when I was reading my Bible. There is a passage in 2Corinthians 12:7-10 that seems to refer a little bit to this concept of "radical acceptance" though that term is not used in scripture. In this passage the apostle Paul describes having a thorn in the flesh to torment him. He says three times he pleaded with the Lord to take it away. But the Lord said to him "My grace is sufficient for you, for my power is made perfect in weakness."

Scripture does not say what Paul's "thorn" or suffering was. We only know something caused him to suffer. For some reason God allowed the suffering but promised Paul that His grace would be sufficient.

I and probably most of us on this forum am always trying to fight this depression and everything that goes with it. I don't know, but maybe this passage is saying accept your problems and suffering, give it all to Jesus, and let His power be made perfect in our weakness.
Don't know if this helps. God bless