If anything, font rendering in Linux is much better than in OSX. It does way more advanced auto-hinting and LCD-subpixel rendering, supports the newest font standards for things like advanced layouts, colored fonts and emojis, etc. etc. There's also very little display fragmentation other than the choice between Xorg and Wayland, which are largely complementary so far. But you can already be on Wayland-only in many cases.