Home loan advice, 18yo

Hi all, I’m 18 years old. For some context I left school at 16 and started a building apprenticeship as soon as I could, saved as much money since then as I could also investing in us stock index’s for two years (currently selling up). I’m going overseas in 6 months with my girlfriend to travel abit of Europe and Asia but when we head home I’m considering home ownership. Currently everything put together and with another 6 months of saving I’ve forecast to have roughly 110k saved up to come home with. As I said I’m a builder so housing would be more of a money maker for me,for example doing up houses or completely building my own ground up myself (talked to bank it is possible). As 110k isn’t enough for a 20% deposit on my preferred price of around 700,000 is it stupid to go any lower than a 20 deposit or any other means of financing, as I’ve said I’ve had talks with banks but I’m cautious they want to sell me loans so will feed me false advice. Any advice helps, cheers!!!