Early 2015 MacBook Pro - Doesn't start up correctly

I have an early 2015 Macbook Pro that I recently updated to Monterey 12.7.4. I don't if it's because of the update or something else, but now when I turn it on: I hear the chime, the log-in screen comes on, I enter my password, and I get this error message: "You shut down your computer because of a problem. If you want to open the applications that were open when you shut down, click open."

It doesn't matter if I hit cancel, open, or if I wait for the 59 second countdown, the same thing happens: the desktop appears with my folders and correct background BUT the menu bar on the top doesn't appear (it's not hidden, it just doesn't appear) and the keyboard no longer works. The track pad works sometimes, for example, I can double click to open a folder but all of the navigation in the right panel is grayed out. Or I can click on Accessibility in settings but can't click Pointer Control - it's not grayed out, I just can't click on it. Or I can open Firefox which loads my gmail, but I can't click on the sent folder or the Promotions tab.

• I have hit cmd+ctrl+esc and relaunched Finder.
• I have run FirstAid.
• I have gone to System Preferences > Accessibility, but I cannot click on 'Pointer Control'
• I try to use Migration Assistant to load a back-up but can't type in my password.

I have launched in Safe Boot and it's a little better -- top menu bar is there, I can use the keyboard, but it's very, very slow. In safe mode:

• I have run FirstAid
• I have gone to System Preferences > Accessibility, under Keyboard, slow keys is not enabled, and Pointer Control none of the options are active except spring-loading delay.
• I have deleted various applications in Safe Mode and updated my internet browsers
• I tried Migration Assistant but it's painfully slow and it always stops working somewhere in the process.

Please help.