BuddyPress.org

Hi guys,

Domain 1 – afci.org
Subdomain 2 – directory.afci.org
Subdomain 3 – community.afci.org

All running wordpress latest.

I wish to connect the 2 subdomains with a single login.
Subdomain directory.afci.org was built with 380 users on wordpress 5.5.1 platform
I recently built community.afci.org to allow users to chat during covid on the wordpress 5.5.1 platform using Buddypress 6.3.0 and bbPress 2.6.5
Wishing one login username and password to allow users to login to one site and be automatically logged into the other, I used a plugin Shared Logins Pro by Codexpert. 
This has be a disaster. The two never seemed to connect properly.
I then saw an instructable https://kinsta.com/blog/share-logins-wordpress/ where I could make Subdomain 3 use the database of Subdomain 2. I noticed that in the databases of wordpress site Subdomain 2 are wp_users, wp_usersmeta but in the Subdomain 3 BuddyPress database they are named wp_user_blogs wp_user_blogs_blogmeta
Q.1 Is it possible that the 2 different database setups conflicted and this why the plugin was unsuccessful?
Q2 Is a solution to rename Subdomain 3 databases wp_user_blogs wp_user_blogs_blogmeta to wp_users, wp_usersmeta and find where they are mentioned in the functions.php and redirect to the new names?
Q3 Anyone have any ideas of how to connect the 2 subdomains or is this not possible with BuddyPress?
I’m excited to hear your ideas.
Thanks so much.
Rachel