If you are using 8x8 LED matrix blocks, you have no choice but multiplexing. It is a pain to design LED PCBs for non multiplexed displays but it is worth the effort.
I'm repairing a full color indoor display now and decyphering how it works, it uses 8x8 matrix 3 color LED blocks and they use multiplexing. I noticed that the same LED lights red or green, when both red and green are on I get blue.
I also repair signs for waiting systems for banks, but they use standard big size 7SD.
My eyes started hearting because I spend too much time looking at LEDs and evaluating quality.
How do you take precaution from such high brightness LEDs?
I make pwm minimum to reduce brightness but sometimes when MCU programming in progress I get all leds on at same time with tremendous brightness OUCH!