Don't ever let a domain go
So,
In 2017 I bought the domain of what today is my startup, in that time I had hopes that I was about to start developing it, but it was not until February 2019 that I started working on it. I let the domain go on 2018 because in that time I didn't want to persue the idea.
Today, AlterEstate is growing faster than ever and we are preparing to move to the Latin American market (right now our CRM only works for Real estate agencies in Dominican Republic)
Guess how much I had to pay for the domain alterestate.com (I was running on alterestate.com.do). The "small fee" of US$ 2,200 😞
The moral of the story is, don't ever let the domain of a project you might start in the future, it might cost you even more to recover it in the future. Don't be cheap investing in your own projects.
I think you got the domain at the right time. You were able to afford it once you got to revenue. Spending money on domains that you can't afford seems foolish. Seems you did the right thing in fact. Let the domain go and if you do make it.. great. you'll be able to buy it again.