Holding gun manufacturers liable isn't going to solve anything. Realistically that would last until the first lawsuit gets to the now highly conservative Supreme Court which will just shoot it down.
And lets be honest here, hand guns and automatics are designed and built to kill people. It seems weird to sue a company because their products worked as designed.
I'm liberal and don't support most gun legislation because I think it's not an issue that can be solved with a few laws. At this point the GOP has made guns a huge wedge issue, and convinced Republican voters that Democrats want to raid their homes, steal their guns and put them all into reeducation camps. Tell a Republican you are a Democrat with a gun and they look at you like you're a unicorn.
Biden's executive orders won't do anything, they can just be reversed by the next President. Even if not, they won't make a dent.
There are only two solutions. Get rid of the guns, or get rid of the environment that makes people use them. Anyone looking at things realistically is going to know that getting rid of them just isn't going to happen. It's just not. That leaves the second option, which sucks because there isn't much we can do THERE either. But at least that is something we could realistically improve.