I am very optimistic for the future of liberalism and humanity for two main reasons:
The kids are alright. Despite copious amounts of handwringing from the political Left and Right that kids (kindergarten through undergrad) are being exposed to "wrong" or "treasonous" ideas, or being "groomed" in school, I don't see extremist (which incorporates both modern D and R parties) attitudes developing in students. They reject both modern Leftism and modern Rightism. They pay the bare minimum lip service to various DEI and other requirements but then go and do their own thing.
The 2nd Law of Demand. The Second Law of Demand states: The longer the price of something remains relatively high, the more elastic the demand curve becomes. What that means practically is that time erodes barriers and costs. Consequently, the barriers to liberalism being tossed up by the Left and Right can, and will, erode as people find (or develop) ways around them. In a sense, this is the Tarkin Principle, named for Grand Moff Tarkin from Star Wars.* People want the freedom to be who they will, and they will find ways around the barriers.
Of course, this is not blind optimism. There are vey real dangers. That many of the people in charge reject liberal virtues (even declaring them vices!) and embrace illiberal or anti-liberal ideas poses a distinct threat. Many traditional allies of liberalism on the Left and Right have betrayed it; liberalism's list of allies grows thin. The attempts to deligitimize the courts by the Left and the rule of law by both sides is a major threat to basic human rights and dignities. These things could overwhelm and we move further back. But, ultimately, I look forward to the future.