It has come a far way, but still far away from fulfilling my needs. If (not that I'll ever get Rain coverage) I were to get a 5G Huawei router I'd just NAT it to my router. I'm more than happy to live with the pains of double NAT just to avoid that limited functionality.
Few things to point out:
1. Don't use PPTP, it isn't secure.
2. Enable IPv6
3. Why do you have a Mikrotik connected but not using it as the "router" that everything else connects to? Nothing against you, I just find it a tad bit tedious to set up ISP-provided routers, if you ever cancel and you need to move to another ISP you are forced to redo configs on a new router. Rather get a decent router and let that router route via the appropriate connection. To most people, double NAT isn't a big issue anymore as most gaming now happens online on company-hosted servers.