My concern is that this describes at least a hundred universities in the USA, and just as many outside the USA (since you are international). As long as you are a very strong student and intend to work hard, then Johns Hopkins and Washington University St Louis do both fit this description IMHO, but so do lots of other universities. Your excellent SAT does suggest that you have the ability to do well at either of these very good universities.
I enjoyed my visit to WUSTL quite a bit, but it was a long time ago. I do not think that you can go wrong with either school as long as you can afford it, and as long as you intend to keep well ahead in your course work. When choosing between excellent versus excellent “a better shot at getting in” does sound like a reasonable concern.
I am torn between “don’t apply ED unless you have a clear first choice” versus “a better shot at getting in”.
I do have a few more specific criteria and aims (research opportunities, internships, world-renowned professors, opportunities for practical experience, a good campus/location, etc.) but the thing is it still applies to many universities, including these two.
And as an international student admission rates are lower for most universities in either case, so I am looking to maximise my chances - ED-ing to one can help with that and WashU has a higher rate so I may end up sticking with that. Once again, I have absolutely no reservations about this - I’ve done an interview with a senior there and it seems like a really nice place with a stimulating environment and community and everything I’m looking for (plus amazing dorms). Also they tend to admit students who don’t ED at much lower rates to maintain selectivity.