The details of what's most tractable for your contact to work on might depend on specifics of their situation (whether they are Republican or Democrat, whether they are more influential with Congress or with the White House or with a State government, whether they are involved with any specialized congressional committees on particular topics, etc). I agree that pandemic preparedness is probably the top general recommendation, but here is a list of some other areas where EA intersects with political issues:
AI, Pandemics, Nuclear War: Unfortunately I'm not sure if there are any shovel-ready AI alignment policies that EA wants to push for, despite the area's overwhelming importance. On the biosecurity side, though, there is a lot of stuff that governments can do. Pushing for some smart pandemic preparedness measures of the sort advocated by Guarding Against Pandemics might be my #1 recommendation. I'm less familiar with the nuclear war / great-power-conflict space and how tractable that is.
Global Health & Animal Welfare: The animal welfare side of EA seems to be celebrating one win after another with their strategy of making moderate, well-researched corporate asks, funding ballot initiatives, and influencing various government food-safety standards. Similarly, global health & development groups have historically gotten a lot of mileage by influencing existing foreign-aid spending to be used more effectively. A lot of global health stuff is appealingly easy-to-understand, which might make it popular and non-controversial: "get rid of lead paint and air pollution", "make vaccines available against diseases", "help people who are suffering", etc. If you want to brush up on how to frame various EA causes in an especially positive and friendly way, Vox's Future Perfect column (which often covers EA global health and animal welfare topics) has a really great style.
General Scientific & Economic Development: The economic policy ideas of the "progress studies" movement aren't big traditional pillars of EA (yet!), but they tend to touch on a wide variety of subjects, so they generate a lot of shovel-ready political recommendations. If you wanted, you could take a shotgun approach and try to just rapid-fire a bunch of suggestions from the playbook of "abundance agenda liberalism", leaving it up to the politician you're talking to to decide whether going YIMBY sounds more doable than trying to reform the FDA, or making it easier to build bigger ports and construct clean-energy infrastructure.
Improving Institutional Decisionmaking: Personally, I'm most excited by big radical ideas mentioned by the FTX Future Fund, like prediction markets, quadratic funding, and charter cities. Unfortunately, these probably aren't the most actionable or popular suggestions! But there are a lot of other ideas out there: Approval voting seems like a good idea that will be broadly applicable. Running better cost-benefit analyses on regulations is always a plus, as is deploying Phil-Tetlock-style forecaster training for important decisionmaking groups. The most actionable ideas for your situation, however, might be something specific to whatever parts of government your contact has influence over -- like changing a specific rule about whether earmarks are allowed for inclusion in spending bills, or when a vote can be held on legislation.