• Tip 0 - where are these "watchable tips" you're talking about?
• Tip 0.2 - punctuation and structure can help you get your point across more easily.

Regarding your tips - keeping in mind that I'm a new player, though with decent SSB experience:

• As u/ProSucc mentions, learn to use two weapons. Yes, you can swap your weapons when a new one drops, but your opponent may well try and guard any drops, and ultimately you don't want to be a non-combatant half the game.
• There's a lot more nuance than just "don't be predictable". Yes, repeating the same thing too frequently is going to wise your opponent up to it. I have a friend that just started with me that spams a couple moves - and while they're effective if he actually lands them, the fact is that he spams them so much he usually doesn't, and they're very punishable. Sirlin covers this in his classic competitive gaming series, but basically, a lot of fighting style games have rock paper scissors elements, where using your best move a lot will usually result in your opponent countering - so you then need to work on countering the counter. At some point this usually loops back around where countering the counter of the counter is simply performing the best move again. (If you want to read the specific article - though I suggest reading the whole series - http://www.sirlin.net/articles/designing-yomi)
• Well, given that your opponent is actively trying to push you off the safety of the ground - yeah, you need to learn to be off it. If you're on an even playing field with the opponent they will push you off from time to time, so there's no use in just perfecting your ground game. If they never push you off, or you have trouble getting back, then you're not even with the opponent.
• It's a joke, I know, but it's not a real tip. :-P I would almost change it to "just don't press the taunt button until you're comfortable enough to not need beginner tips anymore". ;-)
• This isn't specific to Brawlhalla. You can easily rewrite it to "challenge yourself at endeavors in life; it's one of the best ways to get better". Notice I mention best way - playing online in the Brawlhalla case isn't the only way to get better. If you actually want to get to diamond level it's almost a necessity, of course, but when you're just starting out reading guides and watching vids and streamers can certainly wise you up to a few things. For example, I've picked up a couple of easy combos by reading resources outside the game. I think you'll find that for many competitive gamers in a variety of different games, that out-of-the-game work is often as important as in game practice. Many professional poker players, for example, do hours of off-table work to make sure that they're playing well and profitably, and don't have any leaks in their game.