Social events like bars and raves are an option. You’ll find people who just want to get shit faced, but also social people. Volunteer work has a lot of people you can interact with and eventually become friends with. Game places are another option as mentioned. Video games as well. If you have a dog, parks are a way to start conversations and meet people.
Can’t provide input on very bulky items, but It seems you don’t use panier bags or s front basket. Those helped me do much with most items. Some slightly bulky items as well. Add some old tires tubes (free ones with holes from bicycle shops) and I can hold a lot of things.