PF: Is it just a strong recommendation that proposals should be submitted by a representative of the beneficiary (e.g. supervisor of the proposal) or does the submission system prevent the researcher from submitting the proposal themselves?

On p. 5 of the MSCA PF Guide for Applicants it is stated that indeed the proposal should be submitted by a representative of the beneficiary. This should be read as a strong recommendation. Technically however, the researcher can also submit the proposal in the portal as in previous years.