Probably, random orbital sander would do the trick, but slower and chew through a lot of sanding discs. It took me years to finally acquire a grinder - just no real need between sanders and saws. Once I started working on concrete and metal it became necessary, and now it seems like a luxury for all the little things which I probably should have been enjoying a long time ago. But IME, most people under 40 don’t have an angle grinder laying about. So borrow one from a 40+ friend before making the ROS do the work, IMO.

I used a flexible grinding disk.

Tools exist to make jobs easy. There is no virtue in doing hard work for hard works sake. Plus, orbital sanders tend to inflame my carpal tunnel.