Weird as it sounds, the Pen F high-resolution mode is nothing short of amazing. It is suitable for art reproduction, still life, and specific situations in the field. The 12-100mm f/4 lens with OSS is really slick.
The Sony A7r II is impressive--a step up from the A7r.
I've been around the block with just about every film or digital format that's been around for the last 40 years. I am not at all nostalgic for film. I enjoy shooting with an Oly E-M5 II, Pen F, and the A7r II. Admittedly, the Pen F far exceeded my expectations.
As far a "medium format" goes, I used a 48 X 36 CF39-MS Hasselblad back on an H2F and a pancake camera for fine art repro. The color depth from that back is about as good as anything I've seen. However dynamic range, especially in the shadows suffered. It was impractical to shoot above ISO 200, even 200 was often a stretch. The current line of CMOS sensors is excellent. Most mainstream cameras use Sony sensors.
One thing I like about the m43 format is the deep depth of field. I'm an f/64 fan. I like everything in the frame to be in sharp focus. That's the style I've cultivated over the years. I love using the A7r II with super wide angle lenses. The image quality is nothing short of fantastic.
I've discovered that CaptureOne is far superior than ACR/Lightroom for developing Sony RAW files. The proprietary Olympus RAW developer is also better than ACR.
I have zero interest in cropped medium format cameras. The ecosystems are still embryonic. Sure, there is an uptick in IQ. But at the end of the day, I'd rather save money, invest in some glass, and master the ins and outs of the Oly and Sony A7r II.
If you genuinely have to have the very best IQ and are servicing high-end clients on a consistent basis, there are excellent high-end options available. At that level, I suggest finding a VAR or two so that you can test before purchasing.