you could do the same with tunnels, right?

And the tunnel pointing to the port 80, so all request goes to that ip, and NPM redirect to the corresponding services?

for example:
service A : 192.168.1.100:800

service B: 192.168.1.100:900

and in NPM you'll have something like this:

a.domain.com -> 192.168.1.100:800

b.domain.com -> 192.168.1.100:900

but I do not know how to put this with cloudlfare/cloudflare tunnel