On the surface, any Mac can be a file server. Spec enough storage, define your sharing structure, and enable File Sharing. Mac minis with the 10Gig option is nice if you have the switching infrastructure to accommodate the interface.
Sadly, below the surface, the outlook is not as bright as it once was. There is no way to build complex server solutions as Open Directory (and NetInfo before it) is now effectively gone. (Server.app is no longer available). Any Mac-based server you stand up must rely on DSLocal users which means no multi-server setups, no master/replica deployments, no member servers, no Kerberos, no workstation binding, no mobile accounts, no network homes. (Most of these features have been slowing falling by the wayside for years, but the end of Server.app and OD means it is over for good).
This also means the end of Xsan controllers on Mac. Xsan has also been slowly bleeding out for years but through Catalina (and even up to Monterey) it was one of the most effective solutions for massive storage and video-centric deployments. These days are gone.
And this loops to the storage question. You can splurge and load up a Studio with 8 TB of internal storage. But, AFP is gone now that we are on APFS and Big Sur and above. And even if you get an Iodyne for stupid fast storage, you need to reduce the security level of the ARM based Macs because the mass storage frameworks are not done and vendors appear to still need to rely on kernel extensions. (This will eventually change but it is currently an unpleasant deployment hurdle).
With AFP out of the picture, alone stands SMB. I am sure, anyone who used Mac servers in the past can quickly see how inferior SMB is especially when talking about Spotlight results. The sad commentary here is that this is Apple's SMB and Apple's Spotlight. And it is a pale shadow of our AFP experiences. It is always hard (and generally rare) to experience product transitions that result in a lesser experience. But, that is what we have with SMB.
Options? Yes, there are the NAS products. While the offer AFP (very old version) and SMB, each of the services provide their own set of headaches. And they remain bound to your physical environment. This can make supporting a distributed workforce a challenge as this adds the requirement of VPN and this results in the reduction of speed since SMB over VPN is a dog.
For my customers, the road ahead (and for some time) is the cloud. If you are video-heavy, then cloud can be your enemy, not your friend. You must take into consideration your Internet speed (every save is an upload) as asynchronous services can collapse under excessive uploads. However, cloud service that do local selective file sync like Dropbox or OneDrive can allow for massive cloud data sets with reasonable sized local storage solutions. Collaboration across your team can be seamless and users can be nearly anywhere. One note, Apple's FileProvider framework has made the use of external storage impossible (Dropbox is the lone holdout that I can think of and I was really hoping for a FileProvider 2 at WWDC, but disappointment is a familiar friend).
Sorry for the rambling rant. I too miss the days of Apple in the server business. Anyone remember when the Xserve Raid was released? Podcast Server? Streaming Server? Oh, the stuff we were able to deploy, only to find alternatives of abandon completely.
Good luck with your search.