Single-user registration to access all sites in WordPress MultiSite Network

Ok This is what i’m trying to achieve.

A site network where user can post their articles and get rewarded for each post.

For example, Lets say i have a main site example.com. I created a network like site1.example.com,
site2.example.com, etc.

So lets say i have around 10 subsites in my network.
Each subsite have one custom post type.

For example site1.example.com has custom post type videos and only dedicated for videos, site2.example.com has custom post type pictures and only dedicated for pictures, etc. Likewise i created 10 custom post types in 10 of my subsites.

Now i want user access in all network sites with one registration. I mean user who register in site2.example.com should able to access all my network sites and create new posts. They all should be able to access even if i add a new site in my network.

Is there any plugin available for this feature?. Please help me. Thanks