Windows 11 keeps having white screen outs, plus when restoring save points, it removes updates to html. I've troubleshooted my computer so much at this point

Is anyone else having this issue?

Have you tried setting windows compatibility for site designer, I used to get that but haven't had like that for a long time, however you have to do it again if ever windows gets updated.
To help keep previous versions that crash like that overwriting previous versions I always set the project location to be saved to a new folder with the current date. Yes it's a bit of a pain doing it that way, but then so it having to start again and redo required editing
I normally keep the folders for a week then remove the previous weeks folders.

I have windows compatibility set now, and the screen only shows up as black.
I have been trying my hardest to work well within these paradigms but it has cost me greatly, especially in the areas of time.

Zoe
1/ I think you need contact CC Support and report this
2/How much memory on your PC do you have available?
3 open the project file then open "Task Manager> in the "Memory Tab,
check to see how much memory Site Designer is taking, check other apps to see if any other app/files etc are consuming a lot of memory.

As a last resort
open site designer (New Project)
open a template

Does it still show just a black screen?
If it opens normally, then do some editing of the template, (change images/edit text etc,)
does it still work and display normally after a few changes?

In your old (Broken Project) do you have any "Custom Code? if so if you have a copy of that then import it into the new testing project

keep doing things,as one way to try and identify whats causing the issue.

I know this is also time consuming but it could be a way yo see what the root cause could be for your broken project.

When you contact CoffeeCup customer support, you could let them know what you have done, and attach the "Site Designer Broken Project, so that they can check it out.

Finally, if you have access to another PC (even only temporary) then try installing Site Designer on that one, test it out with a template, first, then import things like images/custom code etc etc

At the end of the day Zoe, you need inform CoffeeCup Customer Services about your issue,