Why are so many people so reluctant to download a different calendar app from the App Store? There are many of Apple's apps that are inferior to others in the App Store. That's one of the great things about the ecosystem - an explosion of innovation.
I use Tempo. It's free. It uses exactly the same data as Calendar. In fact, it's dead simple to switch back and forth between multiple calendar apps including Apple s if I'm in the mood. Same data - all the time. No effort. Same syncing with iCloud. Absolutely no downside And with Tempo, I get some additional great features - if I add a person's name to the event, it'll find emails and contact info for me to have at my fingertips - it finds it itself - I don't have to enter any info; if I'm running late for an appointment, it's really easy to send an "I'm X minutes late" email or text; etc
Apple doesn't have to get it all right for all users all the time. There are a lot of innovative developers out there who add value to your iPhone/ iPad - often for free. I use Bloomberg for financial info, TWN For weather, lots of other camera apps, and have done so for awhile - they've historically been superior to Apple's apps for me.
I repeat - download another calendar app. No new data entry, full syncing with everything, often superior features, easy to switch back if unhappy, virtually no effort, no downside.