How would you advise to make fault tolerance?

Question

Computer networks

There is such a topology between three branches.



All routers are microtics.
R1, R2, and R3 each have two Internet channels with white IP addresses.

R1 and R2 are in the same city and are connected by a physical optical channel from Rostelecom, GRE + IPSEC is raised in this channel. This is how R1 and R2 see each other.

R3 is located in another city, and has connectivity with R1 through R1:WAN1 - R3:WAN1, where GRE + IPSEC is raised.

Routes are registered statically everywhere.

There will be more branches, and firstly:
I will raise OSPF so as not to manually slam routes everywhere. When office 3 is tolerable. Then I will be too lazy to go everywhere and prescribe something there.
Secondly, as you can see, if R1 collapses, then everything will fall down, so I want to use two external IPs on each router.

The question is:
How will OSPF behave if, for example, R1 and R2 are connected not only through optics, but also through

1) GRE over Optical, which is now
available 2) GRE over R1: WAN1-R2: WAN1
3) GRE over R1: WAN2 -R2:WAN2

isn't bold?
And if the optics fall, R1: WAN 1 and R2: WAN 2 (suddenly).
How to be?

In addition, there are 3 tunnels between two routers - will it be necessary to raise STP in them and hang it on the tunnels so that they do not ring?

And if you also connect R3 and R2, so that when R1 falls, they remain connected, a loop R1-R2-R3 is also formed - is this also STP?

Answer 1

https://linkmeup.ru/blog/1195/

Answer 2

I advise you to pay someone who understands how to do what you want.
Well, you don’t need to write any nonsense in the TK as you did now. Write immediately what you need to receive. By the way, think about why you need l2 VPN and what topology you need.