Warming aged Gmail

Hey everyone,
I just bought a small batch of aged Gmail accounts (2020–2022), all verified and supposedly clean. I’m trying to warm them up manually before using them for some outreach and light account creation.
I logged into a few using Chrome with residential proxies, and even though I didn’t do anything aggressive, one account got flagged and asked for phone verification after just a couple of clicks. No links, no sending, just checking inbox and browsing.
The seller didn’t provide cookies (and I think no one has Gmail cookies), so I’ve been logging in with user/pass, letting them sit for a bit, clicking around, watching a random YouTube video or two. But I still feel like something’s off. maybe fingerprint or timezone issues?
So I’ve got a few questions:
1. Anyone here warming aged Gmail accounts manually and has a working routine?
2. Should I be using a fingerprinted browser instead of regular Chrome, even with a clean IP?
Would really appreciate any tips.

Chrome leaks a bunch of stuff like timezone, WebRTC, and fonts. If you’re running multiple accounts, I’d definitely go for a fingerprinted browser like GoLogin or Hidemyacc. It keeps each session separate and makes it way less likely to get flagged.

Yeah make sure you're using an anti detect browser but the seller should definitely know the way you should login. I would ask them for he best practices