I have a dual HT/2.2 system running eARC from a Sony Bravia OLED to a Marantz SR8015 AVR, Parasound P5 preamp, B&K Sonata amp (mains) and Adcom GFA6000 for the center and rear Energy surround speakers (Rythmik F12G main sub up front and small M&K K-10 in an opposite corner). Quick thoughts:
1. I recently went BACK to a center channel after using phantom mode for a couple years. The center speaker definitely makes a difference for HT applications and I've determined that I like it much better. Dialog is definitely sharper.
2. Yes, matching the center speaker to your mains is clearly preferable, but not entirely necessary. IMO, one of the most important things is to NOT buy a two-way center speaker with the standard MTM (midrange/tweeter/midrange) configuration. Find a decent 3-way speaker. I stumbled onto a low-cost Elac 3-way center channel speaker that matches very, very well with my Magnepan MMG mains and was very inexpensive. In fact, I like the sound of it better than the Magnepan MMG-C center speaker I used to have (and sold....).
3. HT bypass on a preamp/integrated for a system that is 80% HT is pretty much a "must have". Make life easier for yourself and make sure your new component has it.
FWIW.