Adalo is an excellent app builder for those new to no-code, and you can usually learn to build something from scratch in a day or two. There are a few well-made educational videos on their website, and the templates work well, so it's accessible to just about anyone that wants to build something!
With Adalo, there are a few ways youc an publish your apps. You can publish them to the web (via a custom domain name) and to mobile (via the app store, if you have an approved developer account) or you can share your apps via QR codes or URLs, and download them directly to mobile devices, which can be a workaround to publishing on the app store! Adalo also comes with basic user analytics, simple mathematical formulas, and it connects with a backend Airtable database on the paid plan. Adalo will also automatically create back buttons, home screens, login and signup forms, and more. They make the entire process really easy.
Adalo is a relatively complex product in terms of what you can create, but it does have a few issues. The drag-and-drop interface doesn't currently have many design-focused features, and as a result, perfecting responsiveness on web apps takes a bit of practice. The formulas are a bit difficult to work with, and don't go that far beyond simple multiplication/addition/subtraction - if your app is math/formula heavy, Adalo may not be for you. The backend connection to Airtable is also difficult to work with, and there is limited documentation (as of writing this) on how to get them to work properly - but I expect this to change soon. The mobile apps and web apps you create seem to be separate entities entirely for now and aren't connected natively within Adalo. You could likely solve this by connecting a separate web app and mobile app to the same Airtable backend, but it is an extra step.
The free plan lets you build as much as you want, and I super appreciate that - however, unless you pay for the Pro plan at $50/month, you'll be limited in that: The amount of data you can have on one app (up to 50 rows) and this limits the number of users or listings you create pretty heavily - but if you're building something without a login, it shouldn't be an issue. You also can't publish to a custom domain or to the app store, and you can't connect to the Airtable backend database.