I hope someone gives you the answer you are looking for, but two possibilities popped into my head:
(1) My Logitech Harmony Home Hub, despite not being able to accept/input B&O codes, is able to output them, when you choose, say, a Beovision from its library of pre-programmed devices and drive the TV using the app's virtual buttons. Maybe, if you're lucky, a similar IR output chip/strategy was chosen by BroadLink and their library has been programmed up for you? (If you're already this far in the setup, probably not, but it's worth at least asking the question: do they have any pre-programmed B&O gear?) For that matter, you could just switch from BroadLink to the Harmony, but that requires finding and buying a discontinued product and reading support threads associating Logitech remotes with Alexa skills.
(2) www.lintronic.dk makes converters so your B&O remote can control non-B&O IR products -- and vice versa, which is what you want. You would tell the BroadLink RM that you are using a Sony (or whatever) receiver & CD and tell the Lintronic to accept Sony codes as input and generate B&O codes as output. Given their respective prices, it's sort of putting the cart before the horse,,. but if your hacking efforts don't pay off, you have a backup. (For that matter, Lintronic has a support document that describes how they use Alexa directly, but it seems to require receiving e-mails or SMS as the control stream?)