The biggest concern is old Android devives. By "old", I mean devices using a version of Android from the Obama administration. Android 7.1 is the oldest version that will work, and it was released on October 4th, 2016.
At this point, roughly 6.1% of Android devices are running a version of Android that will be impacted by this change. It's likely that most of these devices are in relatively low-income countries, so depending on your audience this may be much lower or much higher. (If your primary audience isn't in a developing country, it's likely much higher.)
This change will affect you at some point after February 8th, 2024. (Specifically, you'll be affected the first time your LE cert renews after that point. If you're using one of the common clients, it will be up to 60 days after that point.) If you want, you can configure your client to support legacy devices longer, but only up to June 6th, 2024. After then, if you truly need to support very, very old Android devices, you would need to switch from Let's Encrypt to a different (possibly paid) CA.
Only you know for sure if you need to support these very old devices. Most web sites don't.