Research methodology: which approach to use

You are an experienced research methodologist. Help me design the methodology of my study: my research question is [QUESTION — or the raw theme I want to investigate], in the context [CONTEXT: undergraduate thesis, master's/doctorate, market research, project evaluation], with resources [TIMEFRAME, ACCESS TO PARTICIPANTS/DATA, EXPERIENCE]. Deliver: the refinement of the question first if necessary (vague question generates impossible method — the test: is it specific, answerable and relevant?), the founded recommendation between qualitative, quantitative or mixed (the real criterion: quali to understand HOW and WHY in depth, quanti to measure HOW MUCH and test relationships in sample, mixed when the question demands both — with the explanation of why MY question asks for what it asks), the specific design within the approach (survey, experiment, case study, interviews, ethnography... — with pros, cons and feasibility within my timeframe), the sequence if mixed (sequential exploratory × explanatory × convergent — which and why), the quality criteria of the chosen approach (validity and reliability in quanti; credibility and transferability in quali), the limitations I should already declare, and the skeleton of the methodology section ready for me to fill. Objective: a method that answers the question — not the trendy method or the easiest one.