Is there a way to see when the last time an uninstalled app was installed? Here's the situation, I'm trying to work things out with an ex, but her friend saw me on Bumble and told her. I haven't used the app since before her and I started dating, but I must have just deleted the app without ever deleting my profile. It's been uninstalled for well over a year. Is there a way to see the last time an uninstalled app was installed so I can show her that I have not been using it?

Thanks!
The information you're seeking is located inside the library.db which is located at /data/data/com.android.vending/databases. It is part of Google Play Store app's data.
Note: I presupposed that the app was installed via Play Store, as otherwise, this solution is of no use.
For an unrooted Android

Use adb to pull data of com.android.vending (Google Play Store)
  adb backup com.android.vending


convert the backup into tar file using Android Backup Extractor (ABE) or other means you know of.
(ABE needs Java Runtime Environment and has README.txt for usage). ABE would unpack the .ab file into a .tar which you can then extract using an archiver like Ark, 7zip, WinRAR.)

Locate the library.db under databases directory and use an Sqlite viewer software (such as DB Browser for SQLite) to open that file.

Search for the package name of your uninstalled app (com.bumble.app in OP's case) under the doc_id column, and note down the corresponding timestamp in the purchase_time column in that same entry. That is a unix timestamp. Furthermore, a free app is also considered purchased (for zero amount) in this table, so do not be confused by the column name.

Use a site like Epoch Converter to convert the timestamp into human readable form.


For a rooted Android
You can use an SQlite viewer app to view that database. I used MyAndroidTools (not available on Play Store anymore) for testing purposes.