I'm an expat and am curious: Is there any better way out there to manage my various assets in differing currencies across borders and markets? Currently, I just use a spreadsheet, but it is becoming difficult to manage.
There are certainly better ways to keep track of your finances than a spreadsheet. Personal financial management software is a broad category and offers a wide variety of choices, from free to paid.
One way to handle multiple currencies is to maintain a different ledger for each currency that you deal with. Or, if you transfer money frequently, then you may want to choose a program that lets you handle multiple currencies within a single ledger.
Personally I use GnuCash, keeping a separate ledger for each currency. GnuCash has features to combine multiple currencies in one ledger, but I don't need that sort of complexity.
If you only care about your current assets a simple spreadsheet might actually be enough. For personal, but more advanced use you might consider getting a personal budgeting / personal finance software, like YNAB or Moneydance. YNAB is easier to use, but only has minimal multi-currency support (you have to create a separate budget for each currency), while Moneydance is more advanced, and might be harder to start with. If you are just starting a new life somewhere I'd highly suggest to start using one of them, so you can track your spendings, and get a better idea of the real living cost of your new home.
If you have even more assets, or you are actually doing finance-related business professionally, your best bet might need something more advanced, or actually hire someone with the necessary qualifications to do the accounting for you.