I bite my nails, have as long as I can remember, and honestly don't care particularly whether I continue or stop.
That said, I once accidentally kicked the habit for a couple weeks in probably the strangest way possible
I've heard of people getting small magnets implanted under their skin in order to sense electrical/magnetic fields. This idea was always interesting to me but I'm not ready to commit to implants.
But curiosity got the best of me at one point and I got some tiny neodymium magnets and super glued them to my fingernails.
It worked, probably not as well as implants since the magnets couldn't react as well since they were glued down and couldn't wiggle around under my skin, but I could definitely feel some things (strongest reactions I got were probably the forklift charger at my job and an electric pencil sharpener)
I didn't do the neatest job of gluing them on, so there was a bit of super glue covering a good bit of my nails.
And that bit of weird texture from the glue was kind of off-putting and every time my hand absentmindedly went to my mouth it gave me a reminder not to do that.
So for a couple weeks until the magnets fell off and the glue wore away and I got sick of reapplying them, I had nails for the first time I can remember.
Slipped back into my old habits pretty quickly though.
I didn't feel like my life was in any particular way better by having nails, though to be fair I don't have the worst or most-extreme nail biting habit out there, and I didn't particularly appreciate having to trim and file my nails and the crud that managed to accumulate under them.
I don't bite them, but use clippers to cut them down to quick. Am kind of obsessive on doing this. Working as an engineer I hate the sight of oil/grease/muck under nails, so they gotta go.
I've tried so many things throughout my life. Getting yourself to stop is going to be a personal thing. The last thing I tried that succeeded was taking a job out of town where I worked 12-16 hour days. It was manual skilled labor. I was working with my hands, they were often dirty, and frankly, there wasn't much downtime to find myself chewing my nails. This attempt to stop just happened to finally work for me. It's been almost four years.
Keep at it, you can do it!