This maybe odd but I’m a guy deploy RouterOS as firewall/anti-ddos solution. This would be great for fighting with SYN Spoof Flood attack.
You can use FastNetMon for DDoS Sync attack. It has support for rOS.
https://github.com/pavel-odintsov/fastnetmon
M.
When taking a peek at the FastNetMon github issues I have seen that there is an open issue about a specific issue and it’s yet clear to me if it was fixed or not.