You're suggesting that it's somehow more likely that they will cause trouble on the registrar side of the business if you try to move away from those other services. Which may be true but should be more than compensated for by the fact that providers with a large offer of various services are also large enough not to care about you in particular.
Will OVH even notice that I stopped using 10 or 20 of their servers, have someone connect the dots, and put some sort of hold on my domain? I find it much less likely than a small (relatively to OVH) registrar operation simply folding.
What I would advocate instead is to use a really solid registrar for a high-value domain. For example, in Poland our national registry (NASK) for .pl also acts as a registrar. And while their prices are somewhat higher than the competition (~4x), it's as solid as you can get and I know people who keep their short, or otherwise cool, domains registered sometimes well in the nineties there for safety.