FRA - Transit between 1B and 1C, reclear security/immigration?

How long will I need for a non-schengen to non-schengen transit from Frankfurt 1B to 1C? Will I have to expect longer travel times due to immigration or security checks?

I couldn't find a definite answer online, even more so as I expect older resources to be outdated after the opening of the 1C skyline stop in 2017. This one (in German) suggests that a non-stop transit is possible, but it talks about 1A and 1C and does not give actual travel times. Another source reads as if the skyline stop for 1B is in "via departure hall B second level)" - does this include non-schengen?

Edit, as clarification was requested: I am not actually arriving in FRA. As there are no Priority Pass airside lounges in 1C, I was wondering whether the 1B lounges (for which Amex has an agreement) would be an option where I don't have to plan with a longer buffer time for security/immigration. I tried to phrase the question in a more general way so that it can be helpful for others.