So when I am swimming in minecraft bedrock edition with the expierimental caves and cliffs extension. I cannot swim up. The space bar will not propel you upwards and if you look straight up you just stay still

When you swim you can do it in any direction that is not upwards. At first thought, it was a problem with the spacebar but still didn't work when looking in the upwards direction. Then I tested my space bar and it works fine everywhere else.