Obligatory disclaimer: I'm not a lawyer.
5 years in Europe (UK) for the same employer, then posted to the US subsidiary on a L visa. Couple of years on that, then adjustment of status to a green card. All told, about seven years in the US before a green card.
I don't expect the situation to change because of the election. Specifically because European countries are not the Central American nor Asian countries that give politicians pause. If you wanted to immigrate from India or Mexico,
you would have an incredibly hard time no matter who is the next president.
If your aim is to get to North America and leave Europe: then Canada, and specifically Quebec for French speakers, may be an attractive option. The Canadians are going through their own wrangling about the effects of immigration on their society however. So I expect things to get harder. But Quebec is generally very keen on educated European French coming over. Again you might be looking at several years to complete the process.
If your aim is NYC/SF or bust, then going via Canada is an option, but it's not an especially great one, because while you are doing all this stuff with moving and visas and housing etc, the clock is ticking. You might be talking 10-15 years from departing CDG to holding a US green card.
L1 is an interesting visa class because the management version L-1A doesn't (or didn't: IANAL) require your employer to prove to the US authorities that no US national exists to do your job (aka "labor certification"). The specialist knowledge L-1B does. And it is not an easy thing to prove. I strongly suggest that you spend time working at your European employer in a well-documented management capacity before filing for L-1A prior to your posting to the US. You can mutate L-1B into L-1A, but it is very hard.
Re: O visa, there are no guarantees or hard rules of what the US authorities will accept, but more evidence, from peers in your industry, helps. If you think about someone like Mustafa Suleyman, he didn't go the PhD and academic prizes/paper route, but I guarantee that Google/MSFT's lawyers could easily get him an O visa based on his position in the industry. That said, O visas are commonly used for academics that get poached from Europe by deep-pocketed US universities.
This page: https://www.uscis.gov/working-in-the-united-states/options-f... is a helpful summary.