"Download and install: Click on Download and install to start the update process." "Download" could be "retrieve|obtain|access". "Install" as "implement|deploy|execute". "Start" might be "commence|initiate|begin". "Update process" becomes "software procedure|upgrade sequence|installation flow".
Next, "Performance: Updates can improve the overall performance of your device, including battery life, speed, and responsiveness." Proper nouns here are none. "Performance" in the first part might be a title, so maybe handle it as a heading. Wait, the user said to modify all words except proper nouns, so even headings need synonyms. "Performance" could be Performance. Firmware TECNO Spark 30C
I'll apply this process to every word not part of "TECNO Spark 30C". Need to be careful with words like "and", "that", etc. They should be replaced with synonyms. For example, "and" could be plus, but sometimes using multiple "and" variants might not make sense in context. However, the user specified three synonyms per word. So even conjunctions need to be in spintax. "Download and install: Click on Download and install