However, it would not be terribly risky to go half-way to the extreme, particularly if it's the lower limit that's approached. Now, this can have timing effects, so one should proceed with caution.

The main thrust of my prior comment was that the supply voltage and interface levels are necessarily different. Some CMOS devices operate at very nearly supply levels, but it appeared to me that O/P was confusing interface voltage levels with supply voltage.

I'd not recommend pushing the supply of the MCU, in this case, beyond 3V6, while I suspect the LCD will work fine, albeit perhaps a bit slower than specified, at 4.8 volts rather than 5.0. It's not uncommon to see a 5-volt regulator that regulates close to 4.8 anyway, though I never can find one when I could benefit from that. They are, after all, generally 5%'ers.

RE