Require OpenWRT firmware customised will all the below features in it. Let me know if you can do it.
1) WAN Configuration ( Ethernet/SIM with 3G/4G)
2) Internet Traffic failover between SIM1 and SIM2 with defined parameters like Latency, Signal strength.
3) Load Balancing between WAN interfaces.
4) VPN Traffic failover between VPN interfaces based on routing (Static/Dynamic)
5) VPNs ( PPP,PPPoE,IPSec,PPTP,L2TP,OVPN,DMVPN,GRE) with client and server options.
6) VLAN support.
7) Static and Dynamic ( OSPF,BGP) routing protocols
8) IPv6 support
9) Third Party CA Cert and IKE2, SHA1/2/3 support for IPSec/OVPN
10) Source and Destination NAT/PAT options.
11) SNMPv3(MIB/OIDs), NETCONF with YANG/API, TR069 support in firmware
12) Basic Firewall ( DDoS,SPAM,SSH brute,Ping Flood,etc)
13) URL Filtering (Whitelist/Blacklist)
14) IP/user/Application/MAC based policy support
15) DHCP (Client/Relay/Server) Support
16) Diagnostic tools ( ping, traceroute)
17) Router Management via web/telnet/ssh/console
18) packet sniffer and analyser
19) Traffic/Netrwork flows
21) Bandwidth aggregation for multiple SIMs/Ethernet ports.
22) VRRP support.
23) Radius Support.