My understanding is it's smaller even than Pinatubo, which happened in living memory, and significantly smaller than Krakatoa.

Peak power is roughly equivalent to that of Pinatubo apparently. The main difference is the duration, which was much longer for Pinatubo.

Krakatoa is estimated at 200 MT energy, this was estimated as 6 MT.

The 6-10MT estimate is really a lower bound based on the amount of material moved from the island. A more reliable estimate is based on the overpressure, which was significantly larger than the Tsar Bomba (also exploded over an island) which was 50MT. https://text.npr.org/1074438703

That said, the amount of SO2 was fairly low, so the climate impact not likely to be large.

Any idea if this will have a measurably effect on climate change?

I heard from an Anton Petrov video it would reduce the planets average temperature by half a degree for some time, but I don't know where he got that info from.

It's possible that estimate was based on the eruption size, not the SO2 amount. It seems that the amount of SO2 emitted wasn't that much, so maybe something much less than 0.5 degF.

That is absolutely mind-boggling.

Mount Tambora is estimated to have been about 33GT. That one messed up weather globally for two years.

And it's suspected to have had an impact on Napoleons Waterloo disaster by changing the weather...

We have had really beautiful sunsets here in Northern California for the past week. Maybe related? (We also have a winter wildfire in Big Sur that could be contributing.)

Nah, the ash cloud went westwards towards Australia.

The estimate is about 20x smaller