Custom Email Creation Interface

I work with individuals who have disabilities and assist them in obtaining employment. As part of the application process I have to create an email for them because we cannot access their personal email and oftentimes we need to complete assessments or onboarding or follow up with employers on their behalf. We had been creating individual gmails for each customer, however Google has become more restrictive and has blocked access to several accounts indicating that apparently because they are being set up through a singular address they are suspected as breaking their policies. To address this I have purchased a domain with my provider in order to utilize the unlimited emails that I'm allowed to set up for that domain and circumvent Google altogether.

My issue is that I cannot, as part of my daily placement activities create every customer email for office staff and I cannot give access to my domain account login info to office staff. Is there some type of plug-in app interface that can be created where staff can create all of the emails and I either do a bulk upload or the interface accesses the account to create the email? IONOS is my provider.