If you want to use the Nexus Notification system you can take a look here: https://dblurt.beblurt.com/classes/nexus.html

methods:

• client.nexus.unreadNotifications to get the number of unread notifications
• client.nexus.accountNotifications to get the unread notifications with pagination

To mark notifications as read you need to broadcast a custom_json operation

        /** Prepare data */
        const data: CustomJsonOperation['1'] = {
          id: 'notify',
          json: JSON.stringify(['setLastRead', { date: dayjs().utc().format('YYYY-MM-DDTHH:mm:ss')}]),
          required_auths: [],
          required_posting_auths: [this.userConnected],
        };
        const ops: Operation[] = [['custom_json', data]];
        await this.user.broadcast(ops);

Else you can use the notifications system of blurt.blog, in this case I invite you to ask @saboin

For the suggestion I think something about the more active Blurb user or most trending Blurbs but I don't know an easy way to do it