You *can* install the Play Store on GrapheneOS and it will run with "normal" application permissions, rather than the system level that it would have with a typical Android installation.
I don't recommend installing Google Playstore to a de-Googled phone - F-droid is good and Aurora is good if you are careful of the apps you download. I encourage you to keep apps to a minimum, because the vast majority of apps are spyware. I also do not have any banking apps or sensitive apps on my phone, even on a de-Googled phone because if someone steals your phone and gets access to it they can gain access to your banking apps.
I presume that this answers the question on whether a De-googled phone can work with banking apps, crypto buying/selling and swapping apps etc. If this is the reference I thank you for the information.
You can install nearly all apps from Aurora or F-Droid.
Answering your question...nearly all of the Android apps work...but some Banking apps have had issues without having the Play Store installed.
This question may have an existing discussion that may answer your question more specficially.
https://discuss.grapheneos.org/
You *can* install the Play Store on GrapheneOS and it will run with "normal" application permissions, rather than the system level that it would have with a typical Android installation.
https://grapheneos.org/usage#sandboxed-google-play
You can also install the Play Store in a separate profile to add another layer of isolation.
I don't recommend installing Google Playstore to a de-Googled phone - F-droid is good and Aurora is good if you are careful of the apps you download. I encourage you to keep apps to a minimum, because the vast majority of apps are spyware. I also do not have any banking apps or sensitive apps on my phone, even on a de-Googled phone because if someone steals your phone and gets access to it they can gain access to your banking apps.
I don't understand the last sentence about a separate profile.
You can learn more about it by reading previous discussions (I wouldn't be able to say it better).
https://discuss.grapheneos.org/?q=profile
Profiles are also available in Android:
https://support.google.com/work/android/answer/6191949?hl=en
I presume that this answers the question on whether a De-googled phone can work with banking apps, crypto buying/selling and swapping apps etc. If this is the reference I thank you for the information.