Tools like ChatGPT or DeepL Write can correct A1-level German. Copy your sentence, ask: "Is this correct for A1 German? Correct my grammar." Compare the AI’s correction to your intent.
Schubert Verlag offers on their website. For each sample, they provide the corresponding Lösungen for those few pages. While not a full book, this is excellent for testing the format before buying. begegnungen a1 pdf losungen