Diomidis, I share your pain and have spent a lot of time switching between different schemes over the years, trying to find something that works with the different libraries/frameworks that I use (MFC and/or STL/Boost). When working with a single framework, such as the STL, you can try and copy the naming convention it uses, but when you introduce a different framework, it easily falls apart.
In the end I have adopted a single style for all new code that I write (based on the Google C++ style guidelines) and I refactor older code to use this style when appropriate. You cannot reconcile the different naming conventions very easily, so don’t waste time trying. Enforce a scheme for your team/dept./company and stick to it – but don’t get hung up on how ‘ugly’ the code may look when using a mixture of schemes.
The Google C++ guidelines are pretty good IMHO – with some minor amendments. Check the guide out here:
https://google.github.io/styleguide/cppguide.html#Naming