Is there a cleaner, more consistent technology for baseload?

At a certain point, dollars are funny money if you are destroying the environment to save a few now by generating baseload with a carbon-producing tech.

Of course, let’s build the safest and most efficient nuclear that we can, but “its capex is too high” is not a compelling argument to me.

And to be clear: renewables should form as much of the capacity as possible, but a reliable baseload is obviously still needed.

"Baseload" is load, not generation. It's not necessary -- for example the small northern grids that only have diesel generators operate fine even though they have no generators that don't have the capacity for quick cycling.

Baseload was a cost optimization. Back in the day it was cheaper to build coal & nuclear plants that took days to power on. Somebody figured out that if a grid was built of a mix of those cheaper plants and more expensive plants that could start up quicker, it would lower costs. The typical grid was baseload coal and gas peakers. But ~20 years ago gas peakers became cheaper than baseload coal and any need or desire for baseload generation went away.

China is building a lot of coal plants to complement their solar buildout. Notably these are not base load plants. Their new coal plants do not run 24/7, they only run at night.

Similarly, many new nuclear plant designs are not base load designs; they are designs that can be safely and quickly turned on and off.

P.S. the correct term for generation is "non-dispatchable", not "baseload"

we don't need reliable "base load" but peakers - with more renewables more than ever.

Baseload won't be price competitive with renewables in average or shiny/windy conditions ever