Best Equipment/Machine for Repairing Retail Clothes

I've noticed a lot of newer clothes seem to be made sloppier and sloppier. With a lot of poor seam finishing. Several of my clothes have seams starting to unravel within only a handful of wears. Normally I'd say to just purchase more expensive clothes and stop purchasing from said brand, but this issues now appears to have affected all brands to some extent. Even $100 Pants and $150 Jackets and Dresses. QC is now non existent. Also with the new tarrifs who knows how bad prices for new items will get, so I would like to get into repairing my own clothes more often. The only issue is that a lot of modern clothes don't use plain stitches, they are constructed primarily with sergers, especially flatlock seams.

Are there any good machines that can reproduce/repair factory like patterns and strength without needing excess fabric to cut off neatly? Or is the best way to hand repair serged seams? I wouldn't really know where to begin with hand repairing multi threaded stitches, but I'm pretty confident in my ability to hand repair straight stitches and button holes welts etc, so I don't know how much more a plain sewing machine would actually enable me to repair. But clearly I'm not an expert, so that's why I'm asking this sub on its opinions and suggestions for what would benefit me the most.

Lastly, yes I'm aware I could take them to a dry cleaner or tailor and get them repaired there, but there's so many of these stitches that are just starting to unravel that it would surprisingly add up quickly and I am a bit of a perfectionist that I would rather be able to take care of repairs quickly myself without having to make special trips out of my way.