I have been mentoring a few new people lately and found that there isn’t a lot of familiarity with newer bloggers and cross-platform blog following. Back in the day Blogger and WordPress would talk to each other and followers would show up regardless of where their account was based. They severed that connection around 2014 I believe.
The WordPress and Blogger readers are quite robust, although Blogger definitely lags behind due to lack of a mobile interface. Both readers will do their own platform, the other, and Tumblr. However, the Tumblr reader will not accept RSS feeds from Blogger or WordPress.
Following Blogger and Tumblr from WordPress:
Following WordPress and Tumblr from Blogger: