The story seems to be that SV put all their deposits into 10 y bonds in 2021. I'll use that as an approximation.
A 10Y bond will usually move about 8x as much as the underlying interest rate (it's called "duration"). So if SVB did nothing but buy these bonds and sit on them, then they would have lost about 36% on these (8 x 4.5% rate movement). That's a lot but also better than losing everything. And you'd hope the bank wasn't idiotic enough to take no precautions: no hedging of IR changes, putting all assets into just that.
My finger in the air haircut would thus be maybe 15-20% loss of deposits, if this simplified model has anything to do with reality. That's a lot but also means depositors get 80-85% of their money back.
It's possibly pushing the limits of my toy model here but a 10Y bond bought in 2021 is now only an 8Y bond, because time has passed. So instead of 8x you get more like 6x and the pessimistic haircut number is thus 29%.