Because your proposed spread is deep ITM, you are paying almost the intrinsic value of the spread because there's only a small amount of time premium. That means that you have a low delta, low expected profit position with a very asymmetric R/R with a high probability of capturing a small potential gain and a small probability of losing the large debit cost. So if the time premium involved was 30 cents, with a 3 point difference in strikes, ignoring slippage and commissions, you'd have to get this right 9 times out of 10 to break even. Not good odds.
Your spread might be acceptable if implied volatility was high (undisclosed by you), you were outright bearish and you were looking to capture a short term IV contraction. The higher the IV, the higher the small amount of time premium involved in this spread and the modestly lower your debit cost will be.
If you had a downside share price limit as well, say $27 which means that you expect a range of $3 on either side of the current price of $30 then a short Iron Condor might be appropriate since it benefits from time decay on both sides. In addition, if price moves against you, you might be able to roll the unaffected side in, bringing in some additional premium to slow the loss on the affected side.