Black Magic is very expensive. It's a brand for Pro photographers I think. I don't know why, but everything with 10Gbit-Ethernet (adapter/port) is always expensive, while cables for 40Gbit are not.
My two Thunderbolt 4 Docks also only have 2.5Gbit Ethernet.  But backup drives don't need to be that fast anyway.
I meant things like this for example:
	
	
		
			
				
			
			
				
				Synology DS223j NAS Gehäuse für 2 DD 3.5/2.5p 1.4GHz QuadCore 1GB LAN GbE USB 3.2
				
					
						
					
					www.amazon.de
				
			 
		 
	 
Synology is the most used brand I think. This one only has 1Gbit- Ethernet and is a very cheap one.
Most are for at least two drives, but I think they also run if you put just one in. But they are mostly big because  for SATA-Drives because mostly HDD are used for those backup systems. But there are also NAS for blade SSDs I think.
I also found this external HDD what has Ethernet and WiFi, but the ratings are not that good. Looks like there was an SSD too, but it is sold out. Maybe you find something similar or just try it.
I don't know where you are from. If you have Amazon sometimes the model numbers in the link also work if you just change it from .de to .com for example. Doesn't work for this one, but .co.uk works and maybe all EU countries too.
	
	
		
			
				
			
			
				
				Schnelle Anpassung (z.B. Smartphone) 1. Installieren Sie die App, suchen Sie die SSKcloud-App im App Store/Google Play und installieren Sie sie. 2. Drücken Sie die Power-Taste für 3 bis 4 Sekunden, die LED-Anzeige leuchtet blau, dann bedeutet dies eingeschaltet; (wenn die Anzeige nicht leuchtet o...
				
					
						
					
					www.amazon.de