Do you have paying users?

I built something like that for Google Sheets in early 2024 and now I'm thinking whether I missed an opportunity.

No not yet, we are about to onboard the first users on the waitlist one-by-one and when we have ironed out the major issues that we will inevitably discover, we will open up for paid users after that.

I wouldn’t worry too much about missing out, as you probably very well aware, whatever you choose to work on takes incredible amounts of time and energy to get off the ground. Now you just have more time to out into something else :)