You may want to look at Survey123 and the concept of a "public survey" - essentially sharing the survey with everyone. I think it is the only Esri app that supports anonymous, offline data collection as far as I am aware.
With that said, it would be useful to understand why you'd prefer to go down this path. I wouldn't recommend anonymous, public editing of datasets, even though it is possible, as it is quite easy for data integrity to be compromised. If the reason is cost, it would be good to communicate this with your account manager to see if you can come to an agreement on price. If it is the complexity of account management (mobile or within organization), this would be valuable for us to understand within development as well.
Thanks!