A P-core is going to give you better latency than an E-core, because it does the work twice as fast. Yes, if you can split the work, you can get it done faster with 4 Es than one P, but lots of interactive work is hard to split. You can't meaningfully handle a network interrupt with more than one core; you can split your network interface into multiple queues and service each queue with a separate core, but parallelizing within the queue only brings sadness and cache coherency latency.

You might get some interactivity benefits depending on your workload and core configuration... One P vs 4 Es is an easy choice, but 4-P vs 16-E, the 4-P is probably going to feel more interactive because UI latency is lower, even though throughput is lower.