Which platform should be my priority in developing MVP for my new SaaS?

Hello IHs,

I have just started building 'Bettertweet' which is a twitter-based content creation and management tool powered by AI technology.

I recently made our landing page live (Although We have some unfinished changes to do in design)

Visit here: https://bettertweet.io

The SaaS will contain features like

• AI-generated engaging tweets
• Grammatical or language error correction
• Tweet scheduling.
• Some content creation tools for twitter like: Summarization of articles into thread or tweet, Tweet capture tool which lets you capture a tweet and let you frame it as an image to share.
• Idea board feature to write down your tweet idea before you forget about it.

We want to make our SaaS available as an Android app, iOS app, website and a chrome extension.

I would like to ask for suggestions regarding developing an MVP.

For which platform should we build our MVP first.

Considering the USP which is AI-generated tweets & thread writing, which platform would he the best choice to start with, so that we can validate and prove the usability of our service.

Looking for your insightful suggestions ❣

Thanks