Looks like BMW has a new one piece recangring that alone might resolve the issue.
https://help.fcpeuro.com/hc/en-us/ar...wear-explained
The one n52 i worked on would get significant "lifter" (literally "follower") tick but resolved from enough constant drive eg. 30 minutes @ 65 following the TIS bulletin. Always came back when just short drives. (In my case just the lifters)
When rebuilding m62 we replaced the rectangring and the originals were measurably smaller with digital mic.
If you have other cars so you can down time the X, i think you can open it up and measure the parts and determine how bad the ledge v the rings are worn before deciding what parts to replace.
I wonder if anybody makes a "lifter" that's not as slow to adjust as the OE lifters that are famously noisy on the n52 motor.
Are you getting any vanos codes or just the noise?
It's not a terrible tear down to get the vanos gear off, if you have good measure tools to confirm the 3rd party vanos distributor are within spec, it feels like a worthy consideration. It's not electronic so i wouldn't put it in the same class of "mission critical" even though it technically is of course.
It sucks that you'd have to tear down, rebuild and set timing just to try the Teflon seal but if you can buy the distribution part where you can return that's the route I'd take (get the new seals and the distributor, if old ledges not too badly worn just use the seals, else install the China part with the new seals).