The very nature of SPLOTs leads you to want to build your own. Eventually you’ll want something very specific that works just the way you want it to. There are any number of ways to build your own SPLOT. The list below are some paths we’ve found successful.
Gravity Forms + WordPress
Gravity Forms is a WordPress form plugin. You can build sophisticated entry and display patterns with without needing any programming knowledge. The basic license is currently $59 a year and will enable you to create posts from the form entry information. The Gravity Forms templating system (how you merge the data into the post) lets you do virtually anything you can think of. While you don’t need programming knowledge, you can exponentially expand your options as you gain technical skills.
The downside of the more basic/no account implementation of Gravity Forms is that there’s no easy way to let people edit work after it has been submitted. With a WordPress account they can log in and edit their work but adding a secret link to edit the content without an account would require programming knowledge.
Advanced Custom Fields + WordPress
Another option for WordPress is a plugin called Advanced Custom Fields. It lets you structure the backend of WordPress in all kinds of ways. There is a free and paid version of the plugin. With the paid version of Advanced Forms (~$75) you can put your ACF fields on the front of the site as a form to make posts (You can do this with the free version if you know some PHP.).
While there are plugins that help you display ACF fields via various shortcodes, you’ll probably be happier with this option if you understand some basic PHP and foundational elements of customizing WordPress themes.
WordPress Plugins or Themes
If you have the technical knowledge, you can make anything you want using WordPress plugins or themes. Alan Levine has been pursuing this route for the last 5 years. It’s worth checking out his collection of themes. Alan’s gone the extra step to publish blog posts explaining his programming process so others can learn from what he’s done.
Google Forms/Sheets + JS Front End
You can allow submitters to edit their entries in the form settings or allow editing of the whole sheet by specific users.