You need to find the fastest and cheapest way to de-risk your startup idea.
That can be MVP or it can be something else. For example if you're a FinTech lending startup, then you better prove that your loan algos/model are profitable, rather than building UI wireframes and mockups. You can do this by backtesting your models or building a simulation.
"The Lean Startup" book by Eric Ries is already 10-11 y/o, so it's not up-to-date and with lots of gaps.
Also, ignore most of the data-driven methods, as they require lots of data which will not be available for pre-launch product. Instead you need to build a theory about your potential users' needs, and focus on shipping something first.
I suggest to get familiarized with the following methodologies:
- JTBD (Jobs To Be Done)
- 5 Whys
- GIST (Goals->Ideas->Steps->Tasks) method (partialy data-driven)
- Google Ventures Research Sprint
- Google Ventures Design Sprint
If you still decide to ship an MVP - focus on a single most important feature. Use nocode/lowcode tools if possible. Or use some addon/plugin/widget for an existing platform: i.e. a chatbot, Slack/Teams app, twitter bot, Chrome extension, etc.