Not really. There is a compromise between output resolution, refresh rate, bit depth (think HDR), number of displays, and the overall system performance. Another computer might technically have more monitor output, but they probably sacrificed something to get there like resolution, HDR, power consumption or cost. Apple is doing 5K output with HDR on their lowest end chips. Think about that for a minute.

A lot of people like to blame AMD for high ideal power usage when they are running multi-monitor setups with different refresh rates and resolutions. Likewise I have seen Intel systems struggle to run a single 4K monitor because they were in single channel mode. Apple probably wanted to avoid those issues on their lower end chips which have much less bandwidth to play with.

limit it

There isn’t some software limitation here. It’s more that they only put two display controllers in the base level M-series chips. The vast, vast majority of users will have at most two displays. Putting more display controllers would add (minimal, but real) cost and complexity that most people won’t benefit from at all.

On the current gen base level chips, you can have one external display plus the onboard one, or close the laptop and have two externals. Seems like plenty to me for the cheapest option.