Unfortunately, it's rather difficult to draw a dividing line between ordinary voters and powerful ones in a liquid democracy method to satisfy both of these criteria.
There is a curious historical fact, that in ancient Rome secret ballot was introduced in 137 BC only 14 years before Gaius Gracchus, when people being able to vote for reforms but not being able to support that reforms greatly contributed to the downfall of the republic.
Moreover the main reason that we need secret ballot now, is that elections are rare, reward for intimidating someone is huge (4 years of power), and reward for voting differently is tiny and uncertain (one or the other politician not keeping promises). But with issue based voting reward for intimidating is very small as the law can be repealed when people understand that they were forced to do something harmful to themselves, and reward for not being intimidated is much more certain.
Another source of intimidation is the opinion of friends and peers, but if you support a law for which your friends do not want to talk with you, either they are not real friends or you should not support that law. In either case being open is better than lying.
Firstly people will be afraid to support their opinion via voting in many cases because they will be concerned not so much with their friends, but with their employers and colleagues. In Rome only citizens could vote, and sure not all citizens were rich but they were generally speaking not the bottom rungs of society and would be less concerned about their job than many of the poorest citizens in today's society.
It isn't just intimidation it is also a method by which buying votes directly is disincentivized.
Sure technically I can claim to sell my vote now, but the person buying it is taking it on faith I am actually selling it, which means nobody tries to actually buy votes directly. They will attempt to buy votes by say, bribing people in certain positions to endorse them, but they won't try and do so directly.
In Rome there was a clear hierarchy of patrons that was much more influential than what we have in today's society. Secret ballot broke it, and the result was a disaster.
Take a look at https://voteflux.org which explains the idea better than i do. To pass a law you need a large majority to support it, and the rest to accept it enough to not go to constitutional court. And if you are able to bribe such a large number of people continously, it means that they get more profit from the law than from repealing it, so your law is good for society.