I could allow someone access to my network (through windows remote help, for example) to dive into the router and a) get it working and b) teach me what you've done.
Don't do that ever!!! Please...
You have quit heavy/varying needs and what you need is not a UBER driver but a personal chauffeur :-) (aka: full time admin)
Setup an end-point VPN for my iPhone, Android and PCs to connect to my network externally.
indeed this is not the simplest thing to do, but also not impossible. I would say if you don't be able to set this up, you won;t understand
what I guy is doing to your router and home PC, and that is REALLY dangerous...
Optionally, allowing VPN but not for internal access - only to dial back into the UK internet. I've tried this several times and never got it to work properly.
This can be achieved with any VPN provider and no Mtik device needed. Just intall Cyberghost or NordVPN on your phone and select country you want...
Most people don't want IPV6 at home (my case), why do you need/want this?
General setup and housekeeping check
This is simple and forum can help you. If you use default Firewall most things are good!
Sending certain traffic down selected VPN routes, e.g., directing Hulu traffic to a US VPN.
This again is nothing simple. traffic changes, IP addresses, DNS names do change as well (its all the cloud).
You can have this set up once by a person and it might work, but you might find soon it won;t work anymore.
or the method you use is no more the right solution. (example: sent all traffic from that PC to the US, but now you want to print to your local network printer)
So for sure soon you will need to change something...
If you really need all this maybe best is you do a training like MTCNA. Then you know what you do, and you can in the future admin your network.
In your above lines, there are tons of decisions to be taken and various approaches can make this happen.
If you are serious about this, there is no way around paying a "real driver" or learning it yourself.