Can’t speak to the robustness of the rubberized plug, never tried that as a diy’er. I was thinking though if you really wanted a fix it sturdy like, but didn’t want to weld, what are the options? I’m thinking you might could remove the pan and on the bench rivet a thick piece of aluminum already threaded with a hole in it that fits a drain plug, rivet that right over the existing hole, with a gasket in between. It seems like the welding method would be the best though, if you have to remove the drain pan anyway. Here’s what I’d do if I had that problem: Remove the pan, take it to the local automotive machine shop, ask them to fix it so it won’t leak.