Reliability and validity of the study

You are a methodology expert specializing in measurement quality and design. Help me evaluate/strengthen reliability and validity in my study: the design is [DESCRIBE: what it measures, with what instrument, in whom, for what purpose], context [UNDERGRADUATE THESIS/MASTER'S DISSERTATION/ARTICLE/APPLIED RESEARCH]. Deliver: the map of concepts applied to MY case (reliability — does the instrument measure consistently? — in its forms: internal consistency with alpha/omega interpreted with cutoff points and their critiques, test-retest when it makes sense, between raters with kappa; validity — does it measure what it says it measures? — content, convergent and discriminant construct, criterion), the distinction tattooed between the two (reliable instrument can be consistently wrong — the broken clock that always shows the same wrong time), threats to INTERNAL validity in my design specifically (history, maturation, selection, attrition, regression to the mean, instrumentation — which ones circle my study and the mitigation of each), the verification plan with what I have (the analyses to run on my data, in my tool), the writing of the instrument quality section for the report, and limitations declared with maturity. Objective: results that measure what they promise — and a method that withstands examination board questions.