Trust your gut. If you haven't hit 25 subs in this amount of time then yes, your product (ie. comic/novel) will need to change if your goal is to get subs. Maybe this isn't even the comic that will do it for you. It might actually be the next comic you make and you should treat the one you're making as a learning experience, trial run or warmup.
You understand that you don't deserve subs just for existing, which is a good start, so if you follow that logic, the key takeaway is "I am responsible for my comic's performance. I have the power to change my comic based on market research of my audience and improving my craft in art and writing and to create a more appealing comic for this platform."
If you're not a professional-level artist/writer and you're on Tapas, it's pretty much like being a person who plays paintball at the weekend and entering a battle against trained army soldiers. Yes, other genres are less popular than BL, Romance and Fantasy, it's true, but look at the top two or three rows of every genre and you won't see a single comic where the creator isn't making work that's of a professional quality in art, polished presentation and clear storytelling.
You can't stop people from liking BL more than they like your genre, you have no control over that, but you do have control over how polished the presentation of your comic is.
Focus on the things you can improve under your own steam rather than dwelling on things you can't control like the current trends being "hot gay boys" and "I died and got reincarnated as a mary sue in a JRPG!". Trends change (Tapas previously was apparently heavily dominated by slice of life gag comics), but a polished work with strong storytelling is just that forever, and polished works with professional-looking art and presentation have a shot at a staff pick, which is a huge boon to works in less popular genres (mine last week lifted my comic from 275 up to 510 subs, an 85% increase).
To get you started I wrote a 7500+ word guide on making more popular comics on Tapas.