I had this same problem when I purchased a Garmin Edge Explore 2, a newly introduced device from the leading manufacturer. This was their response to my help desk ticket:
"Thank you for contacting Strava. Sorry the data from your device is not being recognized properly on Strava. We do not have this device mapped in our system yet - which can cause your activity statistics to appear differently from what you see on the original platform you use.
I've filed a ticket for our engineers to add this model to Strava. Thank you for your patience."
It took them about a week or two. I think you're going to have to open up a help ticket yourself to get them to put that somewhat obscure off-brand device on there. Good luck.
JBW-Florida (he/him)
STRAVA | User Community

Hello @Rumpled
Thanks for posting about this. @JBW-Florida is correct - you'll need to submit a support ticket to get this device added to Strava.