as far as interoperability across frameworks is concerned, here’s a few examples that i’ve personally ran into before:

training a model in one framework (e.g. transformers) and re-using it in another (e.g. scikit-learn)
using components from one framework in another, e.g. using components from transformers or spacy inside scikit-learn pipelines

for approaches that try to address these issues, you might find ONNX and [tokenwiser](GitHub - koaning/tokenwiser: Bag of, not words, but tricks!) of interest.
hth!