The interface to configure an eSIM is standardized, there is no need to use the proprietary app. You might even be able to configure it with the software included with the phone OS.
The default phone OS software won't allow that. You either need a system app (like openeuicc) or a sim that has an app whitelisted so the OS will allow access (like this product uses)
The manual mentions it includes EasyEUICC hash in an ARA-M slot, so it should work.
ARA-M does not apply to OpenEUICC; as a system app, it can work with any esim.
These all seem quite expensive for what they are. I guess the demand is probably quite low, or are there infrastructure costs involved in supporting these?
https://shop.sysmocom.de/sysmoEUICC1-eUICC-for-consumer-eSIM...
https://esim.me/