Using strictly Keybr.com's available interface will likely not provide you with a drastic increase in speed. This depends on the time you contribute toward practicing in the first place. Personally, I find Keybr's 'Practice' section to be lack luster compared to their Legacy variant, furthermore 'Multiplayer' at least gives incentive to its users to burst or amass more momentum just to partake. It's easy for any stereotypical typist to get bored staring at a solo typing test all day long, and eventually you'll get accustomed to that formula alone whereas the rest of your typing capacity that isn't being tested will suffer. We're not meant to focus on one avenue for typing just to breed results, whether it's doing a generalized typing test or one you composed yourself. For example, if you sat in a chatroom all by yourself and incessantly typed the same sentence over and over (let's say 15 words) and you manage to notice you're exponentially becoming faster at typing that specific line, you'll also find out that the remainder of your muscle memory will be diminished by that. I'd recommend Multiplayer to anybody who comes on Keybr for the sake of improvement, but at least 80% of the users here don't give a flying fuck about improving in realistic terms. They don't do the actual work required, encounter the same dilemmas, and likely will maybe be within their same speed bracket roughly for most of their lives. I've been seeing a "David Martin" come on in the Multiplayer section for years, and I don't believe for one solitary seconds that any recordings I have would suggest he's made any actual improvement, same thing for Federico Figueroa. But hey, don't take my word for it, I'm the only person who comes on this site to the Multiplayer section that REGULARLY does 700-800's in CPM while actually sticking around longer than 30+ minutes to do so. Keybr's Multiplayer should be focused on just like Typeracer's, not their lame-brain 'Practice' section which ignores countless submissions all the time and has some junky ill-formatted scoreboard which makes zero sense. 90% of the people posting here trying to give tips aren't even phenomenal typists themselves, they're in no position to attempt to even preach what constitutes the making of a great typer. If someone can't even type in the 120 WPM range it's heavily probable they have no real wisdom to contribute to your typing development.
Broaden your approach to typing as much as humanly possible, a linear path will generate linear outcomes. None of us greater typists achieved our speed over night, it took years of avid dedication while remaining open-minded. More than half of what you'll read here is counterintuitive, baseless, and comes from a lack of experience overall. There's very few suggestions or questions here that're posed that receive an actual response or answer that's actually relevant. If you just want to practice and not race, then use Typeracer's version instead, otherwise if you're trying to race then use the Multiplayer here or on Typeracer, cause the 'Practice' category here is hot garbage with the worst registry on the planet.