Depends what you’re into and where you’re coming from.
if you’re into history, there’s the site of the Boston Massacre, with the Old State House adjacent; also Faneuil Hall, and the Boston Commons. (Faneuil Hall had a small museum upstairs and an open-air mall adjacent with lots of food places btw) if you like cemeteries, there are colonial-era examples by the Commons and in the North End, there are several historical churches downtown as well. etc.
if you’re into colleges, the Harvard and MIT campuses have some nice buildings, you can usually wander around there during the day.
see if the theater district is showing anything while you’re there. it’s not Broadway, but it’s not bad either.
the Boston area has a wide variety of restaurants from different countries.
think about your hobbies or crafts. then search for a store or club or organization related to that in Boston, there’s probably something related. for example there were several small places that built/repaired antique musical instruments, several gaming shops, several shops for stamps and collectibles etc.
Finally, Boston has a variety of “tour buses” with various themes that drive around downtown, and some that go in the water, they can be worth checking out.
Sure, goth music is pretty varied now. If you look at the bands that play at Wave Gotik Treffen you’ll see a lot of variation: www.wave-gotik-treffen.de/english/past.php That just means it’s a vibrant scene, there are still traditional goth bands though.
Reznor does make movie soundtracks and instrumental albums (Ghosts I-VI) but he still also makes “typical” Nine Inch Nails music. Here’s some examples from 2016-2018: www.youtube.com/watch?v=8JSSCKFgRFM
I decided to get offline more and get more exercise. I found a personal trainer who runs his own gym. He has a media center set up to play music. It plays youtube videos. Without an adblock.
I’ve seen more youtube ads at the gym than I’ve seen when I’m doomscrolling at home.