Churning 4-5 cards per quarter is asking for trouble. You also need to maintain your avg age of accounts.
It's feasible but requires a bit more knowledge and micromanagement.
* Plan your applications to spread the inquiries across the 3 major bureaus.
* If necessary, freeze your credit reports to give you more control of which one gets pulled. You will then have to call the credit card underwriter and give them the PIN to temporarily unfreeze your credit report.
For example, you have too many EX pulls. Freeze your EX report. Apply for a card that is a known EX puller. Get declined. Then call the underwriter and ask them to pull EQ or TU instead. Sometimes the underwriter will refuse; then you'll have to give them the PIN for EX.
There's another strategy that involves getting rid of inquiries on EQ and TU. I'll just leave it there.