The 6210 is current HW spec model. Hopefully you are running the current firmware 10.0.2?
The 2019 server itself will likely connect fine to the 6210. As the iSCSI and networking have not changed.
However, the HIT/ME software is not certified for that OS so I would suggest you wait for the next version of HIT/ME software that should support 2019 before upgrading. Otherwise you may not be able to use those features the software provides with 2019.