Using either ctrl+c and ctrl+shift+v (Configurable from settings), or the the copy styles button in the block editor. Copy and paste the type and styles from one block to another.
Ex. Click a header block, press ctrl+c (to copy), then click a paragraph block, and press ctrl+shift+v.
Note: For apple devices use the cmd key instead of ctrl. ex. cmd+c and cmd+shift+v.
Please post an issue in the GitHub Issues