but the second issue still persists, each time i open image that contains only b/w it switches mode to Grayscale
You seem to be mistaken, if an image is a grayscale image Photoshop opens it as such, it does not "switch" it to some Color Mode it does not originally have (unless you have set up a somewhat complex routine with Script Events Manager – which you probably have not) so your claim of having to "switch it back" is likely counterfactual.
If you want to automate converting grayscale images to RGB you could use conditional Actions or Scripts.
Which could be applied via Batch, Image Processor or linked to the Open Event with Script Events Manager.
