The non-sticky bonus seems really attractive! Does this mean that we will start playing with the deposited money and can withdraw winnings without having to complete any wagering requirement?
Yes exactly. The bonus balance is separate and the regular balance is not affected by the bonus wager.
Where we can the full terms about this 300% welcome bonus offer? I'd like to know about it more because I believe there must be some rules applied to this bonus. I do not see that you have a specific separated page to inform players about this offer, am I missing it or I should have an account to know about it?
You'll need to register to see the rules more clearly, if there are any, because the banner about the 300% deposit bonus isn't clickable.
However, if you look in the TOS, you'll find this.
6. Bonuses and Promotions
From time to time, PLAYZ may offer bonuses and promotions, such as free spins, deposit matches, or other incentives. Unless otherwise stated, all bonuses come with no wagering requirements, meaning you can withdraw your bonus funds and any winnings without having to meet any playthrough conditions. We reserve the right to modify or cancel any bonus or promotion at any time.
https://playz.bet/termssounds like they are very generous because of the bonus without wager requirement