Honestly, I don't have a definite answer for you. It's not recommended to look for free reading sources that might violate copyright laws. It's better to support the creators by using legal paid platforms.
Some libraries might have digital collections of BL manhwa. Also, you could check out social media groups or forums dedicated to BL manga, where people often share recommendations and links to where you can read them. Just be cautious and follow the rules and regulations of the platforms.
I'm not sure if there are many legal and free options. Some websites might offer limited free content, but it's often best to support the creators by using paid subscription services.