I’ll give you a different perspective. I don’t vote in the US elections (given the impact on people in other countries maybe we should) so I won’t focus on the Democrat/Republican thing but on the reasons for selecting a specific candidate.
Step 1 - deal breakers. Determine if the proposed policies cause any immediate regression in what is already achieved. Rolling back existing trans rights, banning abortion, stuff like that.
Step 2 - vibes. This is the critical one. Don’t immediately look at positive policies you want implemented. Look at how a candidate winning would move the Overton Window .
After this election there will be more, and who wins today moves the general vibe of the entire political system. It sets a base for policies of future candidates who might not even know it yet.
Step 3 - narrowing down. Now if you have several candidates that pass step 2 equally, you can look at the specific policies. Generally you can expect any politician to overpromise (khm lie), but usually they try to achieve at least some of the stated goals.
In two-party electoral systems basically you can’t often reach the step 3, but you do have primaries so it can be applied there.