It gets easier with an electoral system other than FPTP (e.g., ranked choice, instant runoff), whereby more than 2 parties appear. You can then mix and match multiple parties that support policies you want in a way that you're aiming for particular policies to become the majority rather than any party.
For example, for issues taxing the rich (TR), taxing the poor (TP), spending on military (SM), spending on infrastructure (SI), privacy protection (PP), and privacy intrusion (PI) and parties A, C, and D, which support TR/SM/PP, TP/SI/PP, and TR/SI/PI, the coalitions the three parties must form to pass individual bills may get you what you really wanted: TR/SI/PP, even though none of the three parties individually support all three.
For example, for issues taxing the rich (TR), taxing the poor (TP), spending on military (SM), spending on infrastructure (SI), privacy protection (PP), and privacy intrusion (PI) and parties A, C, and D, which support TR/SM/PP, TP/SI/PP, and TR/SI/PI, the coalitions the three parties must form to pass individual bills may get you what you really wanted: TR/SI/PP, even though none of the three parties individually support all three.