The thing about being a nice guy is that you don't really stand out from the crowd. You're the generic Man with Hat in movie credits that doesn't really do anything and people don't remember. I'm not saying to start being a jerk, but most nice guys are nice because they're overly concerned with what people think about them. If that's you, stop it. If you piss people off, too bad. A great book on this is Models by Mark Manson. I highly suggest getting a copy and reading it several times. People don't want to be friends with nice people, they want to be friends with interesting people.
Try apps. I have used Hey! Vina and BumbleBFF and had success with both. It's kind of sad that there are a bunch of options for women but not for guys looking for guy friends, but you're a lady. I'd also suggest womens groups at your local community centers, libraries, etc. Meetup.com has meetups in a ton of areas based around hobbies like hiking, knitting, business/networking, mom groups. Mom groups can also be found in ton of places, you shouldn't have a problem finding something like that but maybe you're not looking for kid-related stuff. When I moved to a new city I've used apps, joining a board game night, a book club, and become a regular at a few places. It's helped a ton and now I'm planning my own game night with a bunch of new pals! Can I ask what city you are in?
I tend to think big cities would make it easier, since you have more people who are moving their for work (and thus also looking for new friends) and possibly more going on. When I moved to a new city for grad school, my ways of meeting new people were ...grad student drinking group, swing dancing (big win), and church. Now I'm in a different setting, so I'm kind of lagging in the friends group (no swing dancing), but I have a small group from a writer's group that formed 3 years ago that hangs out sporadically.
You want to look for social spaces were people are also looking for friends. Check meetup.com, look for activity groups you like and see if you can stand to go regularly; ditto, Facebook local groups. It can take a while, but most sane people are super quick to trust, so it's a while before "I'll join you in this group activity" becomes "you can text me to hang out, that's cool".
You might look for gaming stores that host meets, or see if the closest Parks and Recs have an intramural kickball league, I don't even know.
You're probably a people pleaser.
People pleasing gets you hated more than being an asshole.
You don't have to be an asshole, but you have to develop a personality, and then stay true to that personality. Even if someone doesn't agree with it.
If someone disagrees with you on something -- so what? Dont agree just to agree and be liked. Again, that's people pleasing.
Another possibility is that you give to many fucks about what other people think.
Honestly, this is going to require some hard work on your part to get over.
Check out /r/howtonotgiveafuck and maybe check out Robert A. Glover's book No More Mr. Nice Guy.