I did approximately that, but with actual columns, not jsonb, and with a normal view, not a materialized view. Performance sucked on the view because of all the lookups.
So you could create the materialized view which builds the path, and then use an index on the path for subtree selection. However you might find refreshing the materialized view slower than you'd like.
The only real answer here is to build it and load it out with a representative sample of data, or a set scaled down for a smaller test machine, and finding out what the latency and throughput are like for your case. Find out what the ground truth is for you, today, on today's hardware. My tests were from 4+ years ago.
So you could create the materialized view which builds the path, and then use an index on the path for subtree selection. However you might find refreshing the materialized view slower than you'd like.
The only real answer here is to build it and load it out with a representative sample of data, or a set scaled down for a smaller test machine, and finding out what the latency and throughput are like for your case. Find out what the ground truth is for you, today, on today's hardware. My tests were from 4+ years ago.