Serges

You know, there are couple of plugins something like “automatic maintenance”.
You probably check it already, but perhaps one of yours plugin enables maintenance mode?

How exactly did you place the recaptcha on the login page? Via JavaScript code? Is it correct?

As for 3, try to use this https://www.ads-software.com/plugins/badgeos/
As for 2, do you have any examples? Otherwise use this search https://www.ads-software.com/plugins/search/membership/
As for 1, I think, almost every membership plugin has the possibility to log in.

Currently I can see your page and everything is working https://prnt.sc/gpf6oe
Your issue still actual?

When you faced this issue last time, try to recall your last actions. I mean, installing new plugins, changing something in WP, update something?
Or this issue just happened by itself without ANY changes at all?

Can you clarify, how exactly you want these “other options of this same record” to display? Like drop-down list with clickable titles?
Do you have examples of sites or images, where we can see this?

When you write your login and password, open the console and enter the admin area (white screen). check the console for any errors. You can also check the Network tab (in the console).
Then let us know whether you find any errors or not.

Strange, when I tried to enter the screen to enter login and password in your admin area, I was asked to enter another login and password. Is this what I should see? So I can’t event check console)

Do you have any link example of what your friend want to do?
For images, you can try to use file-sharing services.

What do you want to insert in this page? I mean, what kind of products your page will have?

Can you provide a link to some pages where we can see this issue?
Maybe you install or update some of your plugins or theme?

You can contact Bluehost again and ask about backup to restore missing posts and pictures.
Do you consider this variant?

If I understand you right, it’s no difference whether you turn off theme or all your plugins? In any case, memory consumption returns to normal?

You can also check this issue https://www.ads-software.com/support/topic/fatal-error-when-installing-wordpress-2/
Perhaps it can be helpful.

It will be better if you provide more detailed description of this issue and some screenshots.
You tried to install the plugin zip file and had no luck? Do you see any errors?
Or, begin from the start, what do you try to install?