Pickaxe Repair "Too Expensive!"

I've had a real hassle with anvils in 1.16 so far. Recently I tried to enchant my boots manually with an anvil and after 2 enchants (both of which were level 4) I couldn't add the next one (which was level 3) because it was "Too Expensive!" Confused, I went into a creative world and gave myself XP and books. I put myself into survival mode and tried the enchantments yet again. To my surprise, the enchantment went through. Eventually I just gave up on enchanting my boots and went on my merry way.

I wasn't really bothered by it; I could just try to enchant them some other time. But what I wasn't expecting was to be unable to repair my pickaxe because it was, yet again, "Too Expensive!"

Thanks!