chillbrutha - First confirm you're using [Login to see the link]'s tips.
Assuming you are, if you would like [Login to see the link] to investigate, it would be best to write him privately and provide your login credentials (just change your password temporarily, then change it back once [Login to see the link] is finished). This would be the quickest way for him to see what you're seeing.
You mentioned that you attempted to reduce the number of bookmarks. This suggests you may have a large number of bookmarks. Could you share that number with [Login to see the link] -- as well as listing that number in this post? This will help; if anyone else has a similar number, they can confirm whether it works for them and if so, that's not the issue.
I also have my own suspicions about the cause and solution...
Because you're receiving a 500 error, this is not a "handled" error. Therefore, the HTTP logs should make it very quick to find this issue. The problem is that this takes time that [Login to see the link] doesn't have. If provide the exact GMT time of your 500 error, it could help.
One question stands out in my mind:
You mentioned you are able to "uncheck" favorites to reduce the number. Can you tell me where you did that from? For example, my assumption was that you would need to see the list of favorites, in order to remove them?
Due to the type of error (500) and your having tested from an entirely different computer -- I feel you may be right, that it could be related to code. For example, there could be an issue with the back-end query where something being deleted or altered is causing an error in the query that produces the dataset resulting in an unhandled error.
Therefore, if [Login to see the link] cannot get to this issue within the timeframe that you need, you may be able to resolve on your own, as follows:
(1) If you have access to the bookmarks to "uncheck" and remove them, first copy all links to your local PC using any browser extension for that purpose.
(2) Once you have your own copy, remove all links from the favorites. Once all links have been removed, determine if you can then see the UI that shows you have no links, or whether that receives an error as well.
(3) Either keep the offline links as an alternative, or add them back into your favorites (that would be time-consuming, I feel that keeping them locally may be easiest).
Good luck and best wishes 🙂