I am also a big fan of Mikrotik RouterOS systems, they are very simple to setup, manage, and apply firewall/access rules to. I've run multiple ones for SMB's and they are rock solid.
The CRS326-24S+2Q+RM is overkill as he will never get a QSFP+ line run from the Colo to his rack unless it's sub 10M. The cable cost alone will be fucking insane. A 10gbps native RouterOS built device CCR1036-8G-2S+ will give Dual 10gbps connetions to the colocation for redundancy, redundant power, and an m.2 slot for a quick network cache. Downside is only 8 network ports @ 1gpbs. I'd have to look to see if you can bond multiple lines together via the device.
I'll assume
@Null that your server(s) have 1gb network cards in them? Would you be willing to upgrade them, or can you upgrade them, to
10gbps cards?
I personally would stay away from Fiber at all costs unless you want to go full on fiber for everything at which there are other models of Routers to recommend. Fiber is expensive and there is little to gain from using fiber sub 10gbps speed.
At some point you will reach the tipping point of separating your Router from your Switch for 2 devices. In fact that might be a better idea to have TWO routers in a Round Robin mode to alleviate some of the stress on your router. This will require some networking guru work and some special software but you alleviate the bottleneck and make it difficult (not impossible) to take your network down.
PFSense is a fantastic piece of software and very customizable, buy the hardware which comes with a support contract and you'll get some Sales Engineer support as well to advise you on Best practices:
The Netgate 1541 1U 19" rack mount system is a state of the art Security Gateway appliance with pfSense® Plus software featuring the 8 Core Intel® Xeon® D-1541 processor with AES-NI to support a high level of I/O throughput and optimal performance per watt. This appliance with pfSense Plus...
shop.netgate.com
Whatever you do, at this rate,
DO NOT ROLL YOUR OWN ROUTER SOFTWARE AND INSTALL IT ON A SERVER! DO NOT! NO NO NO NO NO. Your life is fucking hell as it is, and to troubleshoot HARDWARE as well as SOFTWARE is a pain in the proverbial dick. If you want to enjoy your time in Estoniastan spend the money get a refurb ENTERPRISE grade equipment and call it a day. It's cute for the house but not for high traffic sites like this. If you like sleep you won't do this.
P.S. Don't hate me for tagging you.