Nice job. I picked up a fair amount of Chinese when I was first learning it using the popular PTT Bulletin board system (批踢踢實業坊) in Taiwan, so it's a great way to learn.

As far as the sentences by HSK level - I did something similar using Tatoeba [1], scraping all the Chinese/English pairs, matching them by HSK level (technically TOCFL level) and adding them to related Anki vocab cards back in the day. Can confirm it works quite well.

[1] - https://tatoeba.org