Seems the new world height is missing which is effecting cave generation.

I have completely deleted old versions and reinstalled 1.17 twice with no change

I can only build up to block 255 and can only go as low as y 0

New blocks and features like geodes, deep slate, copper ores, grow lichen, candles, lightening rods ...ect are around but I'm yet to find any of the new spaghetti and cheese noise caves, aquifers mesh cave or any deep dark cave types.

I assume this has something to do with the height limit issue since it has put a limit on what can generate.

Also lava and bedrock still forming around the usual areas prior to the 1.17 update.

Pics attached are:

A geode in foreground with lava and bedrock in the background around y 0

Directly below the geode at y -6 showing only bedrock above and void below

An example of limit on placing blocks above 255