I will just remake the instructions (tested on Brave and Chrome. Cannot confirm if it works on others):
Step 1: Open Developer Tools on the page of the game. This should be able to be done with Shift + Ctrl + i , or with right clicking and selecting Inspect.
Step 2: Around the bottom of the tools should be a tab called Search. If it is not there, then find a button with the 3 dots and try to find 'Search' there.
Step 3: Search "vue". Make sure you pressed ENTER after typing it. In the results there should be one on line 175 that includes "https://unpkg.com/vue@next" . Click on it and it should take you to the line in the sources tab.
Step 4: First, make sure to create a new folder on your computer. Right click on line 175's text and select Override Contents. For Google, a little information thing may pop up, just click the 'Select Folder' button and select your new folder. A website warning may pop up with 'allow' and 'deny', allow the reading and writing to the folder. If this works, move on to step 5 and ignore the alternate solution listed below.
Alternative solution for Brave, (or perhaps any website if you've overridden stuff but deleted or modified the folder its trying to save to), it may not pop up and instead it will just act like it's overriding to stuff (a warning symbol will appear if attempting to save since it is saving nowhere). If that happens, there should be a little tab on the left side of the developer tools that includes a "Page" tab. Select the two right pointing symbols (>>) and select overrides. Then in this overrides tab, make sure 'Enable Local Overrides' is checked, [if needed, then clear the configuration via the circle with a slash in the middle symbol (Ø)] and press 'Select folder for overrides'. Select the folder you've made. A website warning may pop up with 'allow' and 'deny', allow the reading and writing to the folder. If there may still be issues, attempt to right click and select 'Override Contents' again.
Step 5: In line 175, remove ' @next ' . The quotations should now read "https://unpkg.com/vue"
Step 6: Save with Ctrl + S. This should remove any asterisks (*) from the script name that indicate that the file has not saved.
Step 7: Reload the page (Ctrl + R while focused on it, or just hitting the reload button).
Extra notes: If you ever modify or delete any of the files or folders containing Override Content information, your browser may still think that it should write to whatever you had selected last. This can be helpful if you want to swap between modified and more normal overrides, but in general it can just end up with the game breaking again, so try not to mess with the folders or files.
If this does not work on Brave or Chrome, I assume it is not an issue with the steps. The last guide did in fact show an error for the bad line, but now for some reason it does not. I am not active on this account, so my response will likely be extremely late if I ever do respond.
As of writing, I am unaware if there are any issues that pop up while playing the game. I have only tested that all of the mess gets fixed.
Sorry for the very late reply.