Most probably an SMR drive, as I haven’t heard of any 2.5" HDD that would be >2TB and non-SMR. Consult PSA: Beware of HDD manufacturers submarining SMR technology in HDD's without any public mention Summary: it is discouraged to run a storage node on a drive like that, performance will be abysmal.
On the other hand, this router might be indeed capable of running a storage node, it’s comparable to weaker RPis.