connecting 2 5g routers into 1 switch or router to get doubel speed

Combining 2 (different) ISPs? Very hard to do on NETGEAR routers, if at all. Link aggregation works only with one connection - it's difficult to maintain multiple connections, at least my experience tells me while using it on ASUS routers. Even if you managed to do it, you'll still be limited by the 1 Gbps LAN ports of the router. 

You should look into commercial routers instead of consumer ones.. They may be more costly, but may provide what you're looking for. Check out Ubiquiti, Mikrotik and Cisco. These combined with (multiple) WiFi access points may do the job. (it may require a lot of configuration and fine tuning to make it optimal, though. it's not a "click, click, click solution")