I'd create a timer and allow the person only just enough time to "pass-thru" walls (maybe even while taking some damage created by the plugin) as a ability or ultimate. That would be my fix if I couldn't figure it out.

Without any timer it would have no sense

I solved it by completely disarming nocliped player but it is not solution which I was thinking about. I'll do this better, but need to consider it first. Remaking this buff seems to be best solution, but I would rather not do this by myself

Maybe I'm wrong, but I think that official, global remake would be more universal for all servers than my local.
why not create a new buff that does exactly what you want it to do and then submit that patch?
I've never thinked about submiting any own patches. I think my knowledge of your code is not enough to do this.