I don’t “want to teach myself” I have taught myself, continue to teach myself and haven’t spoken to a boot camp grad that made me feel like I could gain something (outside of connections) from going to a boot camp. That said I’ll contradict myself and say there is no such thing as being “self taught” (or at least it’s very uncommon to just independently discover known things by just thinking with no resources) and that in reality you are leveraging resources that exist and learning from them, and those resources come from other people. I can either leverage free/low cost resources online and learn from them, or pay a massive premium to do the same thing with a group of people and an instructor/instructors to ask questions. Maybe the boot camps in my area are bad but in any case all a boot camp does is give you a curriculum to do and has people to answer questions, I can just do a curriculum myself and find answers online and make connections with people at the meetups I go to, if anything confining myself to a narrow boot camp curriculum would limit what I can do like redirect my focus on areas specific to what I need to know.
Blindly using a hash table for absolutely everything suggests a lack of data structure knowledge (although if you want to be lazy it’s probably the best way to be lazy and get by without terrible performance). I also didn’t say that you “can’t” use a hash table on small data, just that the performance gain is so marginal that prematurely optimization on that level likely isn’t worth it, especially it doesn’t represent the data as well as an Array or list for a mental model. Obviously if you need to repeatedly grab single elements (with arbitrarily random properties) from a large list of elements, a hash map is a perfect data structure for that problem. With web you should be looking at network calls /file size first (serving that static html wrappers before injecting the data that fills the sections, etc) in classical computing the bottleneck was usually waiting for the disk, however if computation is the bottleneck you should prioritize efficient algorithms and using appropriate data structures to make those algorithms fast.