I have better luck with Samsung when it comes to memory/SSDs and TVs. I think you can't beat Samsung when it comes to RAM, flash and LCDs/OLEDs. Samsung SSDs are all made in-house, unlike others which buy 3rd party controllers and NAND from SK Hynix/Intel-Micron Flash/Toshiba. There's reason why Apple and Lenovo use Samsung PCIe AHCI/NVMe SSDs in their higher-end machines.
Making their own controller or not really has nothing to do with the quality, it is more of how much R&D each company wants to spend and what they already make. Intel and Toshiba obviously don't make DRAM anymore and SK Hynix technically make all of them as well (but they are not anywhere close to the best in SSD). On the other hand WD Black is really great but they don't make DRAM at all.
BTW, every computer brand use at least 2 suppliers, and since Samsung has 30%+ market share, everyone has to buy Samsung as well.
Apple bought Anobit, a group founded by M-System veterans in Israel (after they left when SanDisk bought them). Apple wants to integrate the flash controller into their A processor and use it with the NAND they buy from various OEM. I'd not be surprised if their laptop will use this controller with custom file system instead of the standard NVMe command in the future.