I feel like there’s an unspoken ceiling in one of my friendships. How would you handle this?

I’ve been friends with someone for about a year.
Overall, they’ve always been friendly, and we’ve had genuinely good moments. But over time, I started noticing a pattern that I’ve had a hard time putting into words.
It feels like there’s an unspoken ceiling on how close the friendship can become.
Whenever we seem to become a little closer or the friendship starts to feel more meaningful, it somehow stops progressing. They don’t disappear or become unfriendly. There’s still warmth and contact, but I rarely feel like we’re actually building a closer friendship over time.
That’s what confused me for so long.
There was enough connection for me to feel like the friendship mattered, but at the same time, I often felt like there was a limit I didn’t fully understand.
I’ve tried asking for clarity a few times. They still say we’re friends, but I never really felt like the deeper question I was asking was being addressed.
For a while, I thought maybe I just wasn’t explaining myself well enough.
More recently, I’ve started wondering whether I’ve been looking for a verbal explanation for something the pattern itself is already showing me.
Maybe they genuinely see me as a friend, just in a more casual or limited way than I do.
I don’t know whether things in their personal life or relationship status play any role, and I don’t really want to speculate too much.
At this point, I’m mostly trying to figure out how to adjust my own expectations instead of repeatedly asking for clarity.
For people who have experienced something similar, how did you handle a friendship where the other person was warm and friendly, but you consistently felt there was a limit to how close the friendship could become? What helped you decide how much energy to keep investing?