So you integrate with a few systems, you learn where the gotchas tend to be, you call those out as things you'd like to know more about when making your initial estimates, etc. Today's software dev has probably integrated with more systems than they have written linked lists. We just have a habit of forgetting all the little details.

If you're looking for a formula that lets you estimate once and then move on to the "real work" now that that tedious BS is out of the way, there isn't one. But you can still do something. There's ground between "I can't estimate that in 30 minutes" and "I can't estimate it at all" and it's up to you and your stakeholders to come to terms on how to balance the risks in your estimates (in broad terms: too inaccurate estimates vs too much time wasted estimating requirements that have since changed).

(There's a parallel theme in some other comments: "if it's a well-understood problem why am I not using the existing solution?" Similarly, there's a difference between "well-understood" and "perfectly abstractable and automatable", otherwise almost none of us would be employed these days. :) )