If you have a ChatGPT subscription, set up your own GPT with prompting around your level, how you want it to respond, how to correct mistakes etc. Then you can use it for anything - Generate tests based on words you know, roleplay like ordering in a restaurant, write stories and have it correct grammar.
This is what I have to supplement my Chinese and it is incredibly helpful.
Look at the comments already - Everyone is building a simple wrapper to do this very thing but charge you $20 per month for the privelege. These are souless, most likely vibe coded garbage. Avoid.
I want to practice speaking and last time I checked Advanced Voice Mode was not available in custom GPTs - is that still the case? Advanced Voice made a really big difference to conversational practice for me, but I do feel like I need to wrap it in a custom knowledge base/instructions to make it as useful as it could be for my language practice.