You could try looking on some fan-run forums or blogs dedicated to BL manga. But keep in mind that not all of the content might be authorized and could have copyright issues.
Well, finding free and legal BL manga can be quite tricky. Sometimes, some libraries offer digital access to a limited selection. But please note that most unauthorized free sites are against the law and might have risks like viruses or poor translations.
Sadly, finding free and legal places to read BL manga can be quite challenging. Most legitimate sources require some form of payment or subscription to support the creators and publishers.
I wouldn't recommend looking for free manga on unauthorized sites. It's illegal and can harm the creators. You might try some legal platforms that offer free trials or limited free content, like Shonen Jump.