The judgment logic follows two axes: "destination + category." For the EU, look at the CE directive set (electrical LVD/EMC, radio RED, machinery MD, pressure PED, construction products CPR, explosion-proof ATEX) + RoHS/REACH/ErP/PPWR/WEEE; for the US, look at FCC (including FCC ID) + UL (commercial) + FDA (by category) + UN38.3 (including batteries); for the Middle East and Africa, look at each country's COC (Saudi Arabia SABER, Nigeria SONCAP, Kenya PVOC, Tanzania TBS, Egypt COC, Zimbabwe CBCA); for China export controls, look at the dual-use items list. The "Certification Requirement Self-Assessment" tool of the Shuwang Testing and Certification Platform can automatically generate a list based on product and market.
Do not pursue certification based on "what others have done," but judge based on "which regulatory scopes my product falls into." For the same category with different structures, the applicable directives may be completely different.