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.
For me, MangaPark is quite good. It has a user-friendly interface and a good selection of manga. However, the legality of using free manga websites can be questionable, so be cautious.
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.
Webtoons is also quite good. It has a variety of genres and often updates with new content. However, the selection might be a bit limited compared to some other sites.