I have been searching and watching videos and still unclear on the Japan Domestic to International transfer at Narita. I see lots of international to International posts, but didnt catch any with my situation in my search

Greatly appreciate any insights

Booked flights through United
Ana Flight from Osaka ITM To Narita (Star Alliance)
United Flight from Narita to Denver - Non stop in Polaris

Both in Terminal 1

United booking has a 1 hr connection time

I can see due to times for ANA Wings ITM to Narita and only one stop from Narita to Denver, there are no other options. Assuming if I miss it, United will book me through LAX or SFO

Trying to guage the process from Domestic to International

Everything I read says we have to go through security, Immigration and Customs before getting on our International flight to Denver even though we went through security in Osaka ITM as Japanese Internaational and Domestic security reqquirements aare different

Immigration is supposed to befast with a passport or facial ID Check
Customs is a breeze by unless you want to declare something

I see in the videos people walking the secured part of terminal with a Blue Sign to International transfers, but no one shows or describes the process.

Some questions:
1) Is there a fast track security screen within the secured area, or do you have to go out into the main area and come back through the normal security line?
2) Do I have the immigration and customs checks correct?

I know buying both legs through United protects me as far as getting home (eventually) if the first flight is late
Normally I wouldnt do a 1 hour layover, but I would prefer to take the non stop to Denver.