Correct, the difficulty (official term) adjusts every ~14 days so that the average time between blocks remains 10 minutes or so. But the rewards of each block is constant within each halving period. So you can outcompete other miners by purchasing better hardware, or getting cheaper power, but it's a slow grinding process.

The halvening instantly halves the block reward, so everything is twice as expensive per bitcoin. If your margins are thin now, they're even thinner after the halvening.

Here's a chart of the difficulty over time (no endorsement of blockchain.com, this is public info):

https://www.blockchain.com/explorer/charts/difficulty