Get over yourself and hire them.
I've worked part time for several companies and I'd argue strongly against the idea that part timers can't be committed and have an impact on the company.
In my last job, I worked part time and lead a project to migrate the whole company to Git and Ansible for deploys. I then lead another whole project to migrate all the developers from an old dev server with issues to a new shiny dev server using Docker. Actually, that project we took slowly, we migrated a handful of developers and let them try it first, work out any teething problems. Then I was away for a long weekend, I came back, turned out the old dev server had spectacularly fallen over and rather than try and fix it, they had just migrated all the developers straight away without me. It was fine.
With that in mind, another point: having part time workers is great for making sure things are well documented and you don't develop dependencies on key employees.
And I'd agree fully that "passion" is often a red flag. I'd think carefully before joining a company that went on about that. Employees will have a different relation to your company than founders will. You have to acknowledge that.
Also, have you ever complained that's it hard to find good talent? A lot of companies do. They complain bitterly that they can't find the tech staff they need, yet when asked what they do to try and solve this they basically have no answer. Don't be like them.
Start thinking about how you can attract talent now - and supporting those that for whatever reason need flexible and part time work is a great way to attract people. Your current hires reasons are personal projects, but that won't always be the reason. At my current company we have several great workers who are part time - because they have child care needs. They are fantastic workers and contribute a lot. Do you really want to cut all those people out?