I'll say 想通了 and 想明白了, they are the same thing.
想开一点, it is a way to encourage people when they are frustrated, either thing didn't go as planned or something has failed.
Hope this helps.
Thanks for this lesson! but I think this lesson is quite hard, here are some notes after I learned this lesson:
“辞去+(job title )....一职”: (someone) quit (some) job
"留任”：留下来继续任职（remain in office)
When we doubled the verb, we wanted to soften the attitude.
Try to compare 好吧，那买单。/ 好吧，那买单买单。The latter sounds more soft and calm, whereas the prior sounds a bit intense.
There are other examples, such as 你给我时间考虑考虑。这件事我想和你商量商量。