Thanks for elaborating! > However, my immediate reaction to this is that it is easy to fit one particular dataset (in this case part of the Pantheon+ supernova

Thanks for elaborating! > However, my immediate reaction to this is that it is easy to fit one particular dataset (in this case part of the Pantheon+ supernovae sample) with a more complicated model than LCDM, but often these types of models fail when other cosmological datasets are included. This is what I was afraid of. Thanks for the links, in particular for [2]!