Is this a blackhat way? I saw some guys use this way to login at least 2 different adsense accounts without any problems.
Logging in is different from blackhat seo tools. If you just need to login to adsense Google account to see your earnings or something. That does need VPS.
You can use normal way of login, provided that the accounts are genuinely approved. If you brought adsense accounts from someone, then it is totally a different game.
I don't use this way, I know Google adsens easily know this and ban the site. From your advice, I am afraid that I have to cancel my request for windows VPS, i need to rethink about this.
Google is way smarter than people assume. Now it has AI and few more things enabled in tracking, getting caught is very easy. If you are doing something that is against TOS of Google programs.
As far as I know, Google Adsense is one account for one individual. If you are having two accounts for yourself means, something is wrong..
Off Topic:
I want to remind a quote " Hardwork brings success, not shortcuts. Shortcuts cut life short".
Internet is flooded with too many schemes and earning programs that never work in the real world. Don;t ask me why, because I have dealt with people who lost money and time experimenting things that never earned them a cent.
Do something sustainable, even if you earn low. That makes sense and works in long terms. Thanks
Decide yourself, which boat you are sailing, quick buck or ethical earning and then think about VPS and your plans... Good Luck.