I rarely ride mountains when I am not racing them, and I am racing them just fine this year. I would recommend sequencing Sweet Spot Base, Sustained Power Build and 40k TT plans. The pitch of the road doesn’t matter (assuming your gearing allows you to keep churning).
The ability to dole out threshold power for long durations and to mentally handle the high discomfort that causes is what makes a great climber. Also do not ignore core strength, especially low back. Those belly breaths Chad talks about in the ride text help too.