Know which business model you are comparing
Closet companies can look similar in search results while operating very differently. Some use a national franchise system with standardized product lines. Some are local design-and-install firms. Some fabricate cabinetry locally. Others install modular systems sourced elsewhere. None of those models is automatically wrong, but they can affect flexibility, communication and how unusual room conditions are handled.
Ask who measures, who designs, where the components are made and who performs the installation. Those answers help you understand what “custom” means for each proposal.