I have severe anhedonia too.
How to face the concept...
Resorted to drugs. Kratom is pretty much the only thing that works, so I'm guessing any opioid will do the trick.
It is the only way to work up any motivation at all to plan for CTB. However, as it removes 'the evil' as I call my base state of reality, it also distracts you with wanting to take advantage of the very very narrow window of time to relax, fantasize about a better future etc. So it still takes immense willpower to plan. Depends on your CTB plans, in my case the hard part is getting everything ready in terms of arrangements to make it easy for family like will, no mess or worry, cremation prepaid etc.
If you goal is delay, drugs can waste time. I cannot in good conscience recommend them of course.
I'm envious of others with "anhedonia" that are flat or totally unable to feel anything. Because I definitely feel intense sorrow, misery, extreme chronic body pain related to my feeling like scum at all times etc.
In fact attempting to do fun things like travel, eating nice food, going out and even masturbating all just bring about intense agony for a seemingly nonexistent and fleeting moment of minor pleasure, without any sense of relief. Cause is grief at loss of irreplaceable relationship.