I agree.
But as other commenters are pointing out, many liberals are already trying this, but conservatives misrepresent them as being focused on social issues (and misrepresent their opinions on such issues) anyways.
IMO, here are the problems liberals face and solutions to regain popularity:
- Liberal politicians may say the correct things, but what matters is what they do, and specifically how it's perceived. As vice-president, Harris did practically nothing, and the overall perception of the economy under Biden is negative. Meanwhile, Trump is doing almost exactly what he said, even small things like pardoning Ross Ulbricht. Fortunately, you don't need to be the party in power, or even elected, to have well-perceived actions; I believe community-building is the best and easiest way for liberals to regain appeal.
- Liberal politicians may say the correct things, but they don't open themselves up to criticism enough. Liberals (and conservatives, and corporations) have learned to say almost nothing for fear of misspeaking, but this is backfiring; they get attacked for policies they don't state because they don't explicitly denounce those policies, and the policies they do state get misrepresented because they don't clarify or broadcast the clarifications enough. Harris should've went on Joe Rogan's podcast and should've agreed to a debate in Fox News; she would've been judged for her responses, but by not going, she was judged for imagined responses*. Meanwhile, Trump agreed to the debates on CNN and ABC, and he posts and speaks much more often and unscripted (so it's him posting and speaking).
- Wrt. social issues (trans, woke. etc.): "live and let live", and ask for clarification, particularly examples. This area is where people imagine and misrepresent others' opinions the most; so when a liberal politician is asked their opinion on XYZ, they should answer unambiguously, even if it makes them look bad, then debate and clarify. I really think the overarching policy should be "live and let live", and finding ways to accomplish that with minimal federal intervention; because I believe (and hope) it's something most people would agree on**, and because "getting X done" is strictly easier than "getting Y to do X".
One thing that must be said, because the above problems and solutions have been discussed before, but this has been discussed less: these also apply to "the far left", perhaps the same or more than they apply to conservatives. Many people get attacked by the far left who are completely on their side (recent example: ProtonVPN); many others get attacked who I believe are on their side, but must clarify their policies.
In summary: people choose the worst interpretations of their political opponents' speech; if they oppose you, they'll choose the worst interpretation of your speech. However, if you don't speak, your opposers will choose an even worse interpretation of your silence. The ways to remove bad interpretations are: clarify, and far more significantly, act in a way that disproves them. Also, if your general actions benefit people, they'll gradually stop opposing you, so they'll start choosing better interpretations; the same speech is more or less controversial when it's spoken from different people,
* If someone asks you a question and you don't respond, they're not going to forget the whole scenario, they're going to imagine your response based on their existing perception of you. Even if truthfully answering the question lowers their perception of you, if lying or not answering lowers it more, it's the correct choice.
** At minimum, I believe most people would allow any group happiness, if it didn't affect them, said group wasn't hurting another group, and doing so meant they themselves were better off. If most people believe liberal politicians will help their quality-of-life more than conservatives, I don't think they care about social issues; but vice versa is also true, most people won't protect victim's rights if they believe they must non-negligibly sacrifice QOL to do so.