on a Mac mini you would get one level up for SSD at least.
And you may opt to go up a level for RAM.
Your whole database doesn't need to fit into RAM. The RAM caches the portions of the database in use. So FileMaker cache may be a few GB and rest of memory, that is not used for applications, will be used to cache files on disk, e.g. container data.
The M2 is already a lot of faster than your i7 Mac mini.
You may not ned to buy a beefier until you notice performance issues in a few years when your database grew a lot.
In the base (non-Pro) M2 minis, Apple reduced the number of NAND (ssd) module to 2 (from 4 in the Pro), which results in the disk IOPS dropping in half of what the Pro M2 produces. It also has 1/2 the memory bandwidth of the Pro, support for 2 (not 3) monitors, and 2 (instead of 4) Thunderbolt 4 / USB4 ports.
As far as disk space, the external TB4 ports are 40GB/s, which is as fast or faster than the internal SSD, although you would need a TB4 RAID setup to be able to saturate that channel.
As far as memory, FMS will run nicely in 4gb of RAM, although 8 is currently recommended.
As key point of why the Apple SOC processors are so fast, begs a comparison in a rough view of legacy Computer architecture.
Historically, There was a tiny amount of VERY fast, VERY expensive memory in the processor itself, with slower memory, quite expensive memory in the memory controller, along with the code to fetch and serialize the data from the slower, and less expensive main random access memory.
In Apple's SOC, ALL the system memory has been moved into the core processor, so no controller buffered memory, and no external memory. Even the base M2 has a memory bandwidth of 100GB/s ( Pro - 200GB/s ; Max - 400GB/S, Ultra - 800GB/s), resulting in radically faster access to operational memory.
Combined with disk IOPS over > 30GB/s, performance from the M series processors is outstanding.
Intel is headed down the same [copycat] path, with the 13th generation i9s having a similar architecture.
The $100 price difference is not important, and what I'm nost curious about is whether the M2 with more RAM would beat the M2 Pro with less.
With large databases, I'm used to FileMaker Server being very RAM sensitive, but I agree with comments that with the M series macs, the SSDs are usually so fast that VM swapping is much less of an issue.
Recent tear-down review indicated that the base M2 mini has 1 256gb SSD module, vs. 2 in the 512, so the 512gb disk performance should be equivalent to the M1 or M2 Pro