I’m not sure who you mean by “they”. iFixit is great, but they just sold me the tools and the parts, and provided the replacement guides. I have been a customer since they opened their webshop, but I haven’t ordered anything from them for a few years. I can only assume they still have great customer service, if they’re willing to cut ties with Samsung over customer privacy.
Samsung was OK back then. I really liked the device, but it was a little flawed and they offered nothing for the battery that didn’t hold a charge. Eventually the charging port also failed, but by that time I had three spare batteries, so I would just rotate them through the device rather than plug it in. The screen cracking was on me, I dropped it, but the other issues shouldn’t have required a third-party DIY repair channel at all.