First things first - basic compatibility.
"My partner is unwilling to have children, so that is not a factor."
versus
"I would like to have children in the future, but biologically I understand that I could wait at least 10 years to do that."
So, are you willing to gamble that they'll change their mind over having children? Because odds on, they won't. And you'll have wasted your fertile years, during which you could have met another partner who wanted the same things as you. Don't underestimate the resentment that can build where two people want different, incompatible things. Imagine ten years down the line, those ten years that you 'could' wait - and you've waited and they're still unwilling?
On this basis alone, I don't think you should marry.
Next up, your current issue.
"6 months ago, my partner said they wanted to leave their job in order to focus on artistic pursuits, something that they were unwilling to be flexible on"
Well there's a problem, right from the off. 'Unwilling to be flexible'. Relationships involve compromises for both parties. One partner being inflexible and backing the other into a corner where they can say "I feel like my partner has left me with no good options" - that's not a good relationship. Certainly not good enough as a basis for marriage.
Something else to consider, in my opinion:
"My partner and I have been in an international relationship for 4 years, and have lived together for the past 8 months."
An 'international relationship' generally involves long periods apart. That can give the time spent together an excitement, akin to an extended holiday romance. The drudgery of daily life tends to be missing. So I'd be inclined to concentrate on the past eight months, how the relationship has been without the 'international' frisson.
And one last point:
"I fear that I'm approaching this marriage in too cold a way"
No, you're not. I wish more people would approach marriage as you have done, considering the ramifications of marrying or not marrying. Marriage is important, and the decision should be treated as such.