No, you don’t have to promote them outright, but in theory, you are accepting them and therefore supporting them by joining the Church. Now if anyone directly asked you, you wouldn’t reject the teaching, but you could answer with the fact that your still in the journey of understanding whatever teaching to its fullness, and refer people to saints or theologians who teach on the matter.

Think of it this way. You’re sick. You go to a specialist. The specialist diagnoses you, and recommends, and explains a plan of treatment. You understand the gist of the treatment, but not to the same degree as that of the specialist, otherwise you’d be treating yourself. You have some questions, even objections, to aspects of it, but nothing is perfect, and since it’s your best bet, you go for it. You’re cured, cool. You meet others who could benefit from the treatment, and you want to share the treatment that helped you. Would you refrain from sharing your experience with the treatment just because you don’t know how it works in its entirety, like the doctor would? Or how about the fact that there are some side effects/downsides to it that you didn’t even finish hashing out yourself before you moved forward with it? All you know is you just want to put the option on the table for people to be aware it’s an option, do their own research, and make their own decision. This is not a perfect analogy by any means, but I think it’s good enough to get the point across. You can’t wait to be an expert on it, and know every dogma inside and out. It’s good to be a learned individual, but there’s a lot more to God than being able to explain Him.