Understand it one topic at a time focus first on Bitcoin and ignore first other terminology that you mention. Those terms is use for altcoins which you will understand later if you master the basic. Bitcoin the most popular and safest coin in the crypto market which I suggest that you should focus on it first. You can use the search function of the forum or the google search to understand the basics.
Mining difficulty, Coinbase, Cold storage, and hot wallet are all about bitcoin, although altcoins too can make use of cold storage and hot wallet.
Fork is very important to know as well if you want to know much about bitcoin, especially to know that those altcoins like Bitcoin cash (BCH) and Bitcoin Satoshi Version (BSV) are not actually bitcoin but altcoins and not created by Satoshi Nakamoto.
What are purely pertaining to altcoins mentioned in the OP are DeFi and Gas.
I do understand that they are related but the OP seems completely don’t have any idea on crypto especially terminology and giving him the definition of random terminology related to Bitcoin will not gonna mark on him rather than focusing on one topic for research at a time. He will encounter this terminology on the road to his research and that’s the best time to search for the meaning.
I’m sharing base on how I study Bitcoin when I’m newbie. I was overwhelmed too on this terminology when I browse the forum so I make my research slow and focus first on Bitcoin definition and function. I encounter many difficult terminology when doing research but I use google to understand it as well as the context that I’m reading that contain that term. In this way, I can understand further the term and it’s use compared on reading plain definition of terms of random crypto terms.
FYI, My comment that you quoted doesn’t relate on what you post, I didn’t read the content of your post when I made my opinion since I’m already on my reply tab before you made your post. I’m just late to answer here because I saw other thread that I became more interested to reply. I’m sorry if my post looks like I’m not giving credits to your contribution above.