No, it's about being cleverer and putting ideas forward in a way that will gain support and votes. So everyone repeating 'wealth tax' won't gain votes, it will lose them, as too many will see it as the politics of envy and against aspiration. Call it 'unearned income' and you're starting to get there. Go a bit deeper and explain that those with assets should be taxed because they have gained disproportionally from years of quantitative easing, whilst others were paying the price of austerity through years of the banking crisis and covid, and that's even better. Needs a cleverer marketing brain than mine to put that well, but it should be possible.
@Buster15 made a point a while ago about how Thatcher was good at communicating, and promptly got drowned out by childish 'yah boo you're a Thatcherite' stuff, but his point was actually a good one, the left are seriously shit at understanding how most people think and how to get through to them, and until they at least acknowledge that and think about it we're fecked.
edit: although you're right about conviction and ideas too, I might have gone off on one!