What's the best way to protect our IP?

You can probably go one of two ways - patents or trade secrets. Trade secrets, of course, may sometimes be difficult to enforce, sometimes necessitating litigation if someone divulges your trade secrets, and therefore very costly, plus the fact that your trade secrets are no longer secret. And patents of course can be somewhat expensive, but probably a critically important necessary expense, especially if you are getting ready for funding - investors like to see patents, or at least the beginning of the patent process to protect your IP. so you should seriously consider filing at least a provisional patent application. Note that for a provisional patent application, the disclosure must be enabling - that is, compete, accurate, and thorough - because it will serve as a priority basis for your later-filed non-provisional or PCT application. Provisional patent applications, by themselves, will never lead to a patent because provisional applications are never examined - you must effectively convert the provisional application to a non-provisional or PCT application within one year of filing your provisional application.

as in every country there is certainly in Denmark an entity which has the mission to register digital creation (code and know-how), as software are not always patentable, but are certainly protected by copyright. You can also do that with a specialized lawyer. The aim of the registration is to prove your creation and give you a definite date.