There are too many variables...a lot will depend on the political will of the major players and who will still be in government in a few months...for example, in the case of The United States, the Democrats are losing the support of the radical youth but hoping to make up for it with Taylor Swift fans...it’s a conundrum
At least in the United States people very rarely vote on foreign policy issues. There are a fair number of college kids and 20-somethings who are critical of the US' support of Israel, but so far it hasn't affected the vote much. There have been few instances where people voted since Oct 7, but Democrats have done just fine with young voters in those few contests. The best data is in the New Hampshire Democratic primary where Joe Biden was a write in candidate. In all of the college towns Biden did better than he did across the state.
In a system in which there are only two parties that could realistically win an election, negative partisanship is a major factor in people's decision to vote. Negative partisanship isn't voting for someone because they like the candidate, but voting against the other guy because they are repelled by them. When negative partisanship is a major factor people who do vote for a party will often make a lot of noise about what they don't like about that party, but they vote for them anyway because there is no other viable choice.
Also the Democrats are not actively courting Taylor Swift fans specifically, but the demographics of Swift fans have been moving towards the Democrats in the last few years. It's the other side who are attacking Taylor Swift (and the NFL) for some culture war reason. The demographics of Swift fans are a demographic that has shifted dramatically towards Democrats in recent years. Almost half are Millennials, and a very high percent are suburban white women. How attacking a demographic that has started voting against them could move the needle back is beyond me, but that appears to be the strategy.
The issues that Democratic consider most important when voting right now are the perennial issue- the economy, whether the US remains a democracy, and women's reproductive rights. The voters who are low information and tend to make up their mind near election day almost always vote on the economy. If the economy is good, they vote for the party in power, if it isn't, they vote against them. Among developed countries the US has the strongest economy right now. Foreign policy does get talked about, but very few people make up their mind based on that as their primary criteria.
Support for Israel and the Palestinians is a complicated issue and few people understand the intricacies. I'm fairly high information and I don't understand all of it. The bulk of the population only understand it as far as a sound bite and not much more. With a complex issue like this, it is easy to heap a lot of criticism on the administration no matter what they do. This lack of understanding is being exploited by pro-Palestinian actors who are manipulating social media to amplify the negative things Israel has done and dramatically play down Palestinian contributions to the problem.