Pairing of different headphones

I noticed that the H4 gen2 update included some improved pairing. Pairing has been a major annoyance for bluetooth headsets. Feature to pair with several devices. Easy pairing. Etc.

I’m curious how the so many different versions compare. Particularly:

H4

H4 gen2

H8i

H9

H9i

H9gen3

Also, any rumor about updates?

H8i seem at low prices in the market (even new). Do they still face drop-out issues as the early ones? Anything else to keep in mind?