I won't even go on the mobile proxy and all that.
I would just focus on posting responsive content.
This is the only real way you can "warm up" your account.
I'm not just talking about posting on the same subreddit over and over again.
I'm not talking about filling it with highly useful, engaging, and interactive content.
While that may work, it can still come out as spammy.
People will still get suspicious.
Remember, we're talking about Reddit here.
The better approach would be to warm your account in such a way that it looks as legit and "real" as possible.
How do you do this?
As everybody knows, when you have people click on your Reddit profile, they see your posting history.
Now it's gonna look really suspicious when they see your history, posting about the same topic to the same type of threads in the same subreddit.
When you mix it up, they see that you have different interests — maybe you're promoting forex or you have some posts on a forex subreddits, and then this is mixed in with posts on LinkedIn subreddits, job search subreddits, the World of Warcraft subreddits, or Valorant subreddits.
People could get the impression that you are a real person.
You're not just somebody who created an account and is promoting a specific niche product in specific niche subreddits targeting specific discussions.
This is your real identity.
This is your real agenda, but you don't have to be obvious about it.
By mixing things up and looking as real as possible with diverse interests, you are more likely to evade the comment deletion and account-banning hammer.