There were a number of challenges that they had. A recent update from Dec 12, 2022:
https://www.raspberrypi.com/news/supply-chain-update-its-goo...
> Although we are sitting on substantial order backlogs from commercial customers, we expect to gradually increase the fraction of our output which we dedicate to single-unit sales next year until we’re back in our pre-pandemic situation. The chip allocations we’ve received for next year mean that by the end of the third quarter, the channel will have recovered to its equilibrium stocking level, with hundreds of thousands of units available at any given time. At that point, we will have spent a little over two years in a low-stock position: a measure of the severity and persistence of the shortages.