TEXT/JSONB are stored inline IIRC unless they hit a certain size limit at which point they'll be put into TOAST - so you'll see data in clickhouse but some big values might be missing.
do you know if it will in the future? or is this a clickhouse limit of their string data type?
ClickHouse has no limit on sting data length.
MaterializedPostgreSQL engine is just very recent feature with not large adoption rate. I believe if community will use it frequently it will become more bulletproof and more edge cases will be supported. TOAST in replication protocol is just not trivial to implement.