I am using MS Access linked to an SQL backend DB. Thus, design mode is unavailable in Access.

For one of the columns I want to be able to have a drop-down (combo-box) functionality where only the users will be able to select a value from the drop-down list.

I was able to do constraint in the SQL table, which restricts the values that can be entered, but this doesn't create the drop-down list in Access.

I searched and found this

So in above, we have buttons, check boxes, combo box etc. So, you have a lot more flexibly.

You never really wanted to allow or have direct use of tables. They are not in general for appcations and contrlling the user interface, but only a handy way for users to edit data. The instant you want control of the layout, and to use things like buttons, combo boxs, check box as above shows?

Then build your custom form for this purpose. As general rule, you really don't want users to edit tables directly - you have no control over what they can do, and this tends to make applications very hard to write, and control the user experience.