So, here we go. Thanks for waiting. I have been doing several cycling tours around the lake, within the past days, and tried to explore all possible pathes/ways which are directly at - or closeby to the lake. I have the impression, local authorities are doing a lot of effort on finding proper signage as on-site situation didn't match to OSM tagging - or even StreetView pictures (which are not that old, in that area). So, what I'm trying to say is, signage seems to be a bit "dynamic", currently.
Back to the topic here: As visible in my picture before, "main street" is designated route for pedestrians AND cyclists - I guess no argue on that.
About the pathes at the lakeside, these are quite narrow and not made for keeping both parties, cyclists and pedestrians. Due to the high amount of pedestrians, you will immediately give up cycling, once you go there by bike. I really tried, but impossible. That's the one thing.
Second item, which I would like to highlight on, is several indicators around the lake, that these narrow pathes are made for pedestrians only.
i.e.
https://maps.app.goo.gl/qAN9EANPLn2nxCq8A
https://maps.app.goo.gl/noBLD3GUsoDWbwv58 (this one has incorrect direction, by the way)
https://maps.app.goo.gl/mmWSVKMqecKGnMet7

Even though my examples are not exactly related to the pathes pointed out by you, the overall strategy of local authorities is somehow noticeable: having the narrow ones for pedestrians and the bigger ones for cyclists - that'y my impression. 
Being a cyclist and a hiker by myself, I'm trying to find best balance for both parties, to avoid frustration and possibly even anger.
So, setting a bicycle=no is reasonable to me, and in-line with WIKI (Footway: "Description:
A path *mainly* or exclusively for pedestrians.")
As I'm also using bike-navigation Apps like komoot, I want to avoid being routed through these narrow pathes - as it simply causes frustration. There is always an alternative route, just few meters next. Any... 1/2