I'm not sure for German specifically, but some things I've done for studying Korean and Russian:
-If you're okay with SRS, then I find Anki helpful. Personally, I can only really use it intensively at the beginning though. Making and reviewing cards becomes too mind numbing for me after a while. I do still use it after the beginning stage, but I mostly use it for reviewing unfamiliar words encountered while reading and such and stop using it as frequently.
-The language learning subreddits can be useful. There's one for language learning in general and also ones for specific languages. If you have questions, native speakers and more advanced learners will answer them. I would recommend searching the subreddit to see if the question has already been asked though. Repetitive questions can annoy people after a while. I'm not sure for the German subreddit, but the Korean and Russian subreddits also have lists of resources for learning the languages. Similarly, there's a forum dedicated to language learners:
https://forum.language-learners.org/. People there can help with questions, there are lists of resources for various languages, and reading logs of other learners may be useful.
-Another tool I like is Language Reactor:
https://www.languagereactor.com/. It allows you to watch Netflix and YouTube with dual subtitles. You can also choose to hide the subtitles and reveal them as needed. There's also a reading tool, which I would probably use more.
-Podcasts! At the early stages, you can find podcasts designed for learners using more simplified language or spoken slowly, and you can start listening to podcasts for native speakers once you're more advanced.