This is just a quick remix of the original ISA card bracket, to add a little bit of horizontal strength to reduce flexibility and add some extra strength on the screw holes which seems very easy to snap, at least when printed in PLA.

Creality

Ender-3 V3 KE

Yes

Yes

20

Recommended print orientation is the thing edge on the bed
Use brims or rafts for print stability
Use supports for overhanging areas