Legacy software on Catalina requires 32-bit activation

Just got a new MacBook running Catalina after being on a PC for years. I have an activation code for a music software called Sibelius 7.5 from 2015, and would like to move the activated version to the MacBook. Sibelius has had new iterations since then, but I can still download the legacy software fine from the website, and the software runs. But when I go to activate it, it turns out that the activation program, and that only, is 32-bit, so I can't open it! An error message comes up whenever I click the 'activate' button within the software.

All I want to do is type in the passcode and carry on with it :(( It's not feasible for me to buy the software again now, and it was expensive at the time:(.

Is there any way to run the 32-bit activation program on my MacBook such that I can then use the software as usual?