Myanmar also created problem in border with China. Myanmar ethnic cleansing creating issues for Chinese pipeline, transport and port projects. China initiated projects were stalled by new Myanmar regime. So China is not exactly happy the way things are moving in Myanmar. BUT Chinese silence and defacto support for Myanmar going against Bangladesh and Bangladeshis. It should not be lost that in recent past China blocked UNSC statement against Myanmar state terror against Rohigya people.
https://www.rferl.org/a/china-russia-united-nations-myanmar-rakhine-rohingya/28376375.html
Unless China realizes that, it will harm Chinese interest in Bangladesh. There are other players (Japan, India, US ) are waiting on wing. If China thinks it can do away without Bangladesh and Bangladeshi interest, that is another thing we should not completely forget while we deal with China. I am traditionally pro China but Chinese actions or non actions are increasingly going against Bangladesh and Bangladeshi interest.
I agree with TopCat view that Bangladesh should at least (covertly) provide logistical support for these people to stand up on their own. It does not take that much to put up some resistance against Myanmar state sponsored genocide.
Can Muslim countries help? this question is argued for many pages. Truth is absolutely. There are some countries ready and willing to help but current awami league regime blocked their way. For example, Turkish delegation tried to go Chittagong and meet Rohingya's, they had good intentions but were blocked. Similarly, as far I know Iran was willing to help but again current awami league regime which serves indian interest, turned that down.
Current awami regime policy not to allow Rohigys into Bangladesh is utterly flawed one because they also blocking to solve the issue at source.