The US enjoys it’s status in the world due to being an exporter of security for many other countries.
In turn these countries focus on the US, choose US products over others giving the US an enormous trade advantage. Especially because it also incentivises others to purchase US military hardware.
The amount “spent” on Ukraine is peanuts as the bulk is in material support in products that the US government purchases from US companies, made by US workers in US factories.
On top of that the US is investing in this war as it will allow them to reduce future presence in Europe and focus on the Pacific theatre.
I would not be surprised if the current help would be a net gain for the US.
Keep in mind that the ATACMS they sent where near end of life and that meant your tax dollars would be needed to either dispose of or upgrade them. Giving them to Ukraine disposes of them for free, gaining goodwill AND damaging a geopolitical rival.