I think we need to differentiate between types of suffering.
There is unavoidable suffering, like a terminal illness for which all the care you can reasonably get including palliative care, is not enough to remove all suffering. Or even a small unavoidable suffering, like you have a cold for a week and feel miserable. In this case, the person suffering has to find a way to process/ make sense of what is happening. Some ways people do this are by offering their suffering to Jesus, joining their suffering to Jesus, or trying to be an example to others who may be suffering similarly. Mother Angelica had a painful leg disability for most of her life and said she thought God had given her that because he wanted her to be an example to other people with disabilities.
There is avoidable suffering, where something can be done to stop the suffering such as medical care, helping someone to escape a bad situation, or changing one’s own habits (example: you drink every day and suffer because of the resulting effects on your life). In this case I think we have a responsibility to try to stop the suffering.
Finally, there is suffering we willingly inflict on ourselves for a spiritual reason. Usually this is some small suffering like fasting for a couple of days. People use this suffering in all different ways - they can offer it for reparation for sins, for the souls in Purgatory, or as just a way to remind themselves that Jesus is really all they need. There are all kinds of different approaches to fasting and penance. I have my personal favorite or useful ones, someone else may have a different one. if it’s bringing you closer to God and isn’t excessive, it’s all good. If you’re doing more than a small amount of it, you should probably talk to a spiritual director to make sure you’re not doing too much.
I remember Fulton Sheen going past a hospital and saying something like, “All that suffering, wasted”. When we get stuck with suffering that we can’t do anything about, we should try not to waste it. I also take as my examples the Fatima children who tried to find small sufferings like going without lunch and offer them up “for reparation, for the Holy Father, and to save souls”.
That’s my view, if someone wants to argue about it fine, I’m not going to be participating, due to a recent thread that IMHO got way out of hand.