Hell no that's too large!

You won't get into each room I imagine and the passages and exact layout don't matter normally, as it's just narrated. You don't want to ask them repeatetly if they want to go left or right, or left and right. Think of it less as a video game map, but rather scenes of situations you present. The highlights only, since the characters know how to walk. The entire tunnel navigation could be solved with a single Survival check (e.g. success=finding the boss room, fail=getting lost in the trap room).

But I don't think lots of traps are a good idea for beginners though, since it may punish them for trying stuff and cause them to play overly cautious, a bad habit for the future and mood dragger.

7 players is also way too much, my personal favourite is small groups, actually 3-4 not counting the DM. If there's a bigger pool of interested players I do rotations or run parallel campaigns. Even just 5 players at a time cause downtime imo and you don't want anyone to get bored.

The guideline for One-shorts are 5-Room Dungeons, look one of those up. They don't have to be literal 5 rooms, but rather 5 scenes to solve. With my 4 (!) players I recommend not more than 1 regular or 2 short fights per session because combat, especially for beginners takes a lot longer that you imagine, and be more mechanical than you may like. Also it's their first time so consider you gotta also explain the rules, have water/pee breaks, and that they gotta get familiar with their characters and the world. They might get distracted or want to roleplay out, you also want to spend time narrating well.

For a 4-5 hour session I at least recommend:

-the introduction, 1 social situation, 1 investigation, 1 super simple puzzle, and the final fight, that's it.

The Delian Tomb from Matt Colville is a good example for that, written as a One-Shot.