Apple has improved monitor support in the new Mac mini.
According to the manufacturer, the Mac mini with the M4 Pro processor supports up to three 6K 60Hz displays via Thunderbolt or HDMI. For comparison, the previous model with the M2 Pro chip also supported three displays, but could only work with two at 6K 60 Hz and one at 4K 60 Hz.
Also thanks to the M4 Pro chip, the new Mac mini can live three Pro Display XDR displays or three Studio Display displays, or control two Pro Display XDR displays or three Studio Displays.
As for the standard version of the Mac mini with the M4 chip, it is also compatible with three displays, but with two with a resolution of up to 6K at 60 Hz via Thunderbolt and one display with a resolution of up to 5K at 60 Hz via Thunderbolt or 4K at 60 Hz via HDMI.