How to wire new switch
The 2 blacks From the switch go to the red and orange.
Doesn’t matter clip the reds straighten and use a wire nut to combine the 3 wires. Then black to orange with a wire nut.
The white on the switch goes to that group of whites
If you have a white on the switch, last the green to the ground or bare copper.
That it was a 3 way doesn’t matter if the other switch was removed and you have an always hot.