Europe is extremely important to Israel. Their legitimacy stems from seeing themselves as European. Their loss of support from Europe is very bad in the long term.
Yes, US is supporting them to. They are losing from both sides, though. They may have part of the remaining generation in power and that's it.
The US is no longer a reliable partner. Once the current administration is gone the likelihood of US support is less than guaranteed. Even with this administration in place support is less than guaranteed. All it takes is the right moment to set off a tantrum and friends become enemies. Israel really doesn't have allies so much as accomplices and that type of friend only sticks around when it helps them.
Trump is as far right as you can go and still support Israel. If America goes further to Tucker Carlson and Nick Fuentes land Jews will wonder why they let so much evil be done in their name by the Israeli government.
Carlson has never been that strongly pro-Israel as I understand it. He's carefully toed a line that maintains a solid right-wing fanbase. See e.g. this [0] from 2012 and this [1] from 2019.
Of course that was just one example. But Carlson has definitely let loose since his Fox News days and, if you're aware of what's going on, you'll know that there is a significant section of the US right wing now that is anti-Israel. This isn't in doubt.
On the flip side, I'm not saying they are pro-Palestine, it is definitely an America First agenda. However, the unified front on Israel is finally broken. For the best, I'd say.
So what did they really lost? Do they even care that some Europeans don't like them ? Europeans are not the one who sell them 99% of their weapons.