I believe they can use practically uneven pixel distribution by lenses. So if they render the “middle” over a larger area and later correct for that with lenses than in effect that part will be of higher pixel density.

I highly doubt it. The average pixel density is 33 pixels per degree (compared 60+ ppd of a no-frills monitor at a typical desk distance). Concentrating pixels in the centre to make a reasonable display would leave something like 10ppd for the periphery, which is like 1/5 of eye's resolution.