Speed comes from rhythm
Fast typists are rarely pressing keys faster; they are pausing less. The gaps between keystrokes are where most time is lost, usually while deciding on a key or recovering from an error.
Practicing familiar words at a steady, even pace does more for speed than straining at unfamiliar text.
Raise the ceiling, not the average
Alternate between comfortable text at a relaxed pace and short bursts slightly faster than feels safe. The bursts stretch your limit; the comfortable runs make the new pace repeatable.
Know what is normal
Typing speeds vary widely and no particular number makes someone good or bad at typing. What matters is whether your typing keeps up with your thinking, and whether it is improving over time.
Speed also depends heavily on the text. Familiar words, ordinary punctuation and no numbers will always produce a higher figure than an email full of names, dates and amounts. Compare like with like when you check your progress, and treat one result as a snapshot rather than a verdict.
If your speed has stalled, look at your errors before pushing harder. Most plateaus are caused by repeated corrections on a small set of keys, not by a limit on how fast your fingers can move.