Unknown creaking noise

Back here to ask for help with my bike creaking noise as heard in the video.

Nich legend 4 2022 frame.

Noise sounds metallic? Idk – the video has the noise. Seems to be resonating/coming from the rear, maybe hub? Or not sure if its BB – its a press fit bb86. Noise comes only when im pushing downwards for both sides, dont hear it when im pulling the pedals with one leg only. no noise at all while freewheeling. Noise occurs on and off, but usually only starts 5-15 minutes into my ride when the bike is 'warmed up'. Holding rear brake and pushing the pedal doesnt make the same noise. off saddle noise still there. its like one long creak during the downpush usually

What i've done so far:

1. Used same pedals on a different bike – no issue

2. tried reinstalling casette with grease on the freehub splines – my entire freehub kept coming off a few times (3 pawl, chinese brand, similar hubs to dtswiss i guess). had all 4 bearings in the hub changed in late november. but since then, while washing my bike/reinstalling casette, freehub has fell of like 5 times or so and i had to reinstall it with toothpicks to push the pawl down, maybe that caused it to dry up though it still seems to spring back well. havent had any freehub skipping or whatsoever.

3. my frame, purchased second hand, came without the thru axles, had to port it from my old bike. however, swapped to a 165mm axle with 16mm of threads for the rear, when it supposed to be 164 with 14mm of threads (from nich itself), and the pitch is the same, hopefully not the axle causing the issue since i cant find the same length. Front doesnt have noise, but new axle for thats coming soon.

Cant do much without having to replace part by part at my shop, which is abit too costly for me.

Anything that can be done to help diagnose/fix the problem will be greatly appreciated, thank you!