i've been thinking about buying historical gold coins as a store of value, but i'm not sure where to start

hi everyone i've been thinking about diversifying a some portion of my long-term savings into physical gold as a store of value while researching, i came across historical gold coins such as sovereigns, vreneli, napoleon 20 francs, and similar european coins what caught my attention is that some of them seem to have two potential sources of value - the gold itself - a collector premium that may increase over time i'm not talking about extremely rare museum pieces worth tens of thousands of euros