I have a rather complicated question and would appreciate any help. (I will bolden the important and relevant parts to make it easier to follow.) I'm an international student currently studying at a PhD program in Canada (2nd year). Due to the low quality of the current department, in the past few months I have been preparing to apply to some top US/UK programs this year, which I will know about the results by March or so. But some time ago I also had applied to another PhD program at an Australian university that is a good program but pales to the top US/UK programs in my field, and I just received an offer from there and will have to make a decision about the offer in a few weeks.
My question: if I go to Australia and within a few months get an offer from a US/UK university, would it be feasible to get a US/UK visa? It would be a back-to-back student visa applications: Canada (two for two years), then Australia (for a few months), then US/UK. Would the US/UK visa agents be suspicious of this pattern? Would this make getting a US/UK visa more difficult or even impossible? (Please ignore the moral profile of the thought, aka., ditching one program after another; I'm just thinking about the visa challenges at this stage.)
To make things even more complicated, I should add that I have Iranian citizenship, and already struggled to get my Canadian visa; getting a US/UK visa is statistically more difficult for people of my nationality.
NB: I'm not asking for advice on whether or not I should do as above, but rather whether or not this pattern can make getting a visa hard or impossible.
Please do let me know if anything is unclear or if I should make adjustments to my post.