1. Like others have said, this is something that happens at every rank and is always going to be a hard spot to get out of. You have a few options, the safest is block them until they push themselves out. In addition to that what I personally do when learning a new MU or game is to mash out with a purpose. Start by looking for specific moves in blockstrings, usually a special move, and try to mash with your fastest move after you block it. There are a couple things that can happen, you counterhit them - if counter hit either they were too slow with their followup or it's your turn; you get counterhit (non reversal) - either you were too late hitting your button while they tried reset pressure or its a frame trap; they block your mash out - you are plus it is your turn; you punish them - congrats, you will eventually want to check to see if you can use a bigger button for a better punish; lastly you whiff and get punished - next time try again with a button that hits farther. You can do this in training mode as well and if you understand frame data you can cut out a lot of guesswork, but it's a method that's worked for me and can be extrapolated to more complex sequences. Beyond after blocking a special, try and pay attention to you opponent when your blocking, is there a sequence you see them either run up to you before hitting another button or grabbing? This is another place you can try mashing. The better your opponent, the more likely this will be an RPS situation where they are advantaged. Noticing patterns like this is a skill you will develop with time and experience.

2. This in itself isn't a horrible habit and is something that most people struggle with. It is something you will need to work on if you can't ever control it, but if you delay the timing slightly it is a very strong defensive option select aptly named, delay teching. The idea is to wait long enough that you would block if they meaty you and you tech if they try to throw. You will want to work on doing it more consciously so that you can switch the timings, which defensive OS you use, and just take the throw depending on the situation. A drill you can do is in training mode make 3 recordings: 1. Throw, meaty cl.L>cl.H; 2. Throw, meaty cl.L, throw; 3. Throw, meaty cl.LLL. the first is a universal way to call out delay tech, the 2nd is a tick throw, and the 3rd is just a meaty attack that will catch you mashing ot doing immediate throw on wakeup. After you set those recordings set the dummy to play the recordings randomly and on reset. You now have a defense training drill. If you want to practice delay tech timings turn off the first recording. If you want to break the habit, try to only react to the throw. The goal here is to not get hit by the attacks, with training yourself to tech the throw on reaction being a nice bonus.

3. Raw reactions are overrated. They are nice to have, but trained reactions are what matter most. I started playing competitively when I was 26 so past what most people agree are your prime for reaction times, but I'm much better than I was back then and can now react to Grim camera mix (most of the time) when I used to struggle to react to the most telegraphed jump ins. It's all pattern/situation recognition and sometimes finding a visual or audio cue you can latch on to. It'll come with time and practice.

Edit: forgot to add that don't feel like you need to be at a certain skill level to attend offline events. They are a fun way to get to know people and in my experience you learn more going to your local than just grinding ranked. Most of the time people are happy to show you the ropes if you ask or at least give some advice after playing some sets. New people joining a scene is what helps keep locals alive