D53G-5HacD2HnD-TC&EG06-A Chateau LTE6-US 802.11a/b/g/n/ac (5) 10/100/1000 Ethernet Ports

This router is great! You should do a simple firmware update and the latest MikroTik RouterOS will be installed. Winbox is a nice way to administer this router, it works in Linux too using wine. Or just use the ssh console or http webfig interface. It isn't the most capable model of router MikroTik offers but it still works great for what you're probably using it for, to put in a sim card and get LTE service as the WAN interface, or one of the WAN interfaces, like as a backup when the main Internet connection is out. I think it is however currently the most powerful router from them you can get with a cellular radio that works well in North America. You can connect a pair of SMA cables to an external LTE/4G antenna which I plan to do for use in the car. There is a better model with faster 5G capability but that's for using cell service in European service areas. I use it for car Internet access for myself and guests and it works great for that. Just know you need a step up voltage converter so that you get 24V DC for this. There are no mounting holes; you'll need to come up with a mounting solution if used in vehicle. So far mine was just sitting on the back seat.

Bought "New in Box", received one with SIM slot heavily damaged.

I don't have high expectations of cellular internet connections, generally. This MikroTik device performs well in the context I put it in. Sitting inside the combined network/broom closet in our home, with at least two interior and one exterior wall in its way, it manages 25mbps - enough to act as a proper backup. We aren't a long way from the nearest cell tower, but that is not what this device is meant for (unless fitted with external antennae). Also, it has the wonderfully-flexible Mikrotik RouterOS, which supports some direct access to the modem, for us tinkerers.