The 25k limit is not enforced. At the moment it’s merely a suggestion because as you approach 25k rows you will likely hit a bottleneck. (Even well before depending on the complexity of your app) It’s possible that Glide will enforce this limit later on but hopefully they will raise the limit because of improvements to their technology and pricing plans. I can’t say for sure.
Will they be using the GlideApp to add these records or does it come from another source?
You may want to consider using =filter to bring into Glide only what’s necessary.
I.e. the last 7 days
Glide only counts rows that are used in someway by your app. It’s possible to have many more rows that exist in your database. @Uzo is demonstrating it’s possible to have over 160k rows in GSheet and still have under 500 rows counted by glide.