What is the best gear combo for me on road bike?
It's a question about physiology first and hardware second. The people that really are better off with a high gear higher than you have now are some combination of pros and/or low-cadence pedal mashers. Figuring out what cadence is really right for you given adequate conditioning is one of the key questions in cycling, and one that you can read endlessly about.
A closer cassette will give you the benefit of closer intervals between gears. If you don't need the 34 with the terrain you ride, that is all upside. The 50/34 compact, 11-34 cassette setups are good for a certain kind of cyclist and terrain, i.e. casual or beginner road cyclists with major hills or mountains to deal with, but can be serious overkill for other use cases, like rolling terrain and/or a stronger cyclist.
If the Apex group you have is still in good shape and you're finding you don't need gearing as low as you have, there's a lot to recommend just getting an 11-28 or 11-25 cassette rather than completely reinventing the bike, plus a new chain. I'm fairly certain that the WiFli type Apex RDs can handle whatever large cog you want to go down to and not have overly large gap.
A good way to begin to learn how to answer this question for yourself is when you're on your rides, keep track of what gear combination you use to climb the hills you work with, and, on the opposite end, if you find your high gear isn't high enough, what gear combination is that (50/11 for you). Then go home and plug those numbers into a gearing calculator and you will know what your ideal range is. If you need or really want to switch groups, you can let that be your metrics.