How to grant access to internal resources on guest wifi?

Question

Computer networks

There is a wifi network (guest), which implies full access to the Internet, some popular dns (8.8.8.8), to the internal network without access, but with access to internal resources (via external) that are available outside.
What needs to be done to make these resources available?
In short, in the office, it is organized like this:
The provider submits statics (10.10.10.1), a range is allocated from the provider, which is used for external services (20.20.20.1-20.20.20.10).
nslookup dns name resolves, but tracert fails.
PS alternative organization options will also be useful.

Answer 1

Didn't get your description.
A guest network is a network WITHOUT ACCESS to the local network, but with Internet access.
It implies access to resources available from the Internet - regardless of where they are located.
In order for internal resources to be accessible from the outside (from the Internet), you need to publish them there - through NAT.
If you need access to the local network from the guest network, the easiest and safest option is to set up a VPN on the local network with access via the Internet (you can limit it to the ip address of your router).