Web (browser) push - best method?

I’m looking to implement a web push functionality to send a push to user when they have a new notification. I have a list of “Notifications” for each user, and ideally I would like to have them receive this push whenever their “Notification” count is higher than before the push, i.e. via a Data Trigger workflow.

I’ve looked into Onesignal plugins and am unable to hook it up. (By the way, do I need to write "'<head>" and "</head>" in the app settings/page header, before and after the inserted script? Either way, I tried with and without, to no avail.)

Firebase seems to require to install through “NPM”, I do not know if Bubble has such functionality.

Any suggestions on what route to take? Whether it is through a plugin or an API call. Thanks.