Wanting a dw but dates??

Either would be perfectly fine, it all just depends on what works best for your budgets. If you decide to go with Summer 2021, I would have your Save The Dates sent around Summer/Fall of 2020 to give your guests plenty of time to prepare financially and book travel/lodging. Otherwise, you can wait until Summer/Fall of 2021 to send them out (about 8-12 months before your wedding)

As Amber mentioned, it depends on what works for you and your budget. I got engaged August 2018 and planned a destination wedding (live in NYC, getting married in Charleston, SC) for 10/10/2020. Although it's a 2-year wait, it allowed us to truly research venues so that we can do site visits and book the big things early (e.g., venue, wedding planner, photographer, etc.).

Only thing I experienced was that it also put us in the mind frame of "oh we have 2 years, we can do this later" and we put a lot of things off until the 1-year mark. For example, I wanted to send my save-the-dates in October so we could give our guests a year to plan, but didn't end up sending them out until right before Thanksgiving because we waited too long to put an official guest list together - and that was with nagging/pushing my fiance to give me his guest list haha