Don’t do the mistake to always use short sentences just because you’re told that’s easier to understand. No. That applies to newbee texts, but not to enterprise and expert texts or technical blogs. Main clause, subordinate clause, that’s a good metric. Your Sentences are best if they range between a minimum of 9 and a maximum of 20 words. Unless you’re telling somebody the basics 101 of knitting or are doing populist rants in tabloids.
Wikipedia has pages on that topic, like the German https://de.wikipedia.org/wiki/Textverst%C3%A4ndlichkeit, but also German press agency DPA is used often as a reference: https://www.netzproduzenten.de/blog/laenge-von-content/.
In English, “the median sentence length in journalism is above 15 words”:
https://en.wikipedia.org/wiki/Sentence_(linguistics), Websites like languagetool even suggest that the typical English sentences has about 20 words, but that may also be due to the abundance of short words in English:
https://languagetool.org/insights/post/sentence-length/. Mind that Languagetool suggests the shorter the better, but at the same time they also advise to alternate short and long sentences. So if now you’re totally insecure, I’m sorry, then please refer to the Chicago Manual of Style.