This shouldn’t be expanded upon here in this thread, otherwise it would be off-topic. However, it would be worth a separate thread, and I would personally be interested to know why it shouldn’t be possible to control Tuya with a RS90. Tuya does provide an API for Tuya products. Price-wise, Tuya is even cheaper than a Broadlink Mini.
I own a Broadlink Mini, even though I don’t actively use it anymore. So, yes, any additional external IR hub supported by the RS90 is a feature gain, as long as the Hapitque IR extender isn’t available yet.
As mentioned, there are already IR hubs that can be controlled by an RS90 if a user already owns one. Regardless of Broadlink, I would find it helpful if Cantata provided a short guide on how to easily control such devices with an RS90 and thus send an IR command. This would at least save some users from having to purchase another device, since they can ultimately control the device they already own with an RS90.