Oh, I'm not talking about using only LLMs, for sure. I am currently taking a college sequence (currently French 3), with textbooks, homework, and everything. 100% agreed on the value of traditional texts/flows. On the matter of LLMs being permissive with grammar, you need to use the tools specifically meant to check grammar. I use LanguageTool for everything I write to make sure my grammar is both correct and current.
LLMs are invaluable IMO for immediate feedback on your writing and speaking. I've started using French inputs for most regular interactions, even with things like Claude Code for my work and for all LLM interactions (I use Grok). Before I input into Claude Code, I check the grammar and content with LLMs. Tutors and traditional paths will not help with this.
The other sequence I'm starting to do is to have conversations as I take baby steps in speaking/listening. Agreed that talking to real French speakers is the best, but initially we tend to be shy because we're so bad, and using a non-human can put us at ease. You may be different, but IMO this is typical. And this post was about refining this via an app that adds spaced repetition, and I appreciate that.