Don’t forget Baptists - they’re the biggest Protestant denomination, at least in the USA.
One big difference between Protestant and Catholic Sunday morning services is the focus. In most Protestant churches, the “centerpiece” of the Sunday morning service (which we don’t call “Mass”) is the sermon. The service usally begins with praise and worship, usually musical in form. Lots of singing, though the style of music varies greatly from one church to another. following the music, the preacher delivers the lesson, usually lasting between 30-45 minutes; sometimes it’s shorter, sometimes it’s longer.
As I understand it, the Catholic Mass (as well as other “high church” services, like Orthodox, Episcopal and Anglican) focuses on the sacraments (taking communion, or The Lord’s Supper, for the Protestants reading this). Rather than a “sermon”, the priest delivers a brief “homily” on one topic or another. The homily is usually much shorter than a Protestant sermon.
Simply put, Catholic services focus on Communion, Protestant services focus on praise and teaching.
I frequent a site called “Ship of Fools - The Online Magazine of Christian Unrest”: link The site is British, and tends to lean more toward Anglicans, Episcopalians and Catholics.
One feature of the site is “The Mystery Worshipper”, where “agents” visit churches around the world and then submit “reviews” of those churches. One of the questions they answer is, “Exactly how long was the sermon?” Most of the reviews are, again of Catholic, Anglican, Episcopal and Orthodox churches. I was surprised when most of the sermon lengths mentioned were between 6 and 15 minutes. Having been raised a Protestant, I couldn’t believe that a preacher would preach such a short sermon. So I posted a question about it on their forum, and got the answer I gave above.
One woman, who I believe was Catholic, described the first time she visited a Protestant church and was surprised to discover that “…the entire service consisted of a concert followed by a lecture.”
Also, most non-high-church Prostestant churches observe Communion only about one Sunday each month, rather than every single week. We also shun elaborate ritual for the most part. Aside from The Lord’s Prayer, most Protestant churches favor impromptu, off-the-cuff prayers over standardized pre-written prayers.