There is motion and transform tweening (scale, position, rotation) but no interpolation of drawn frames. Render speed depends on hardware and animation specifications
There are a lot of video tutorials if you look. Any answer you need can be found with a search xD
Tahoma2d and opentoonz have more features expected for professional animation: https://www.youtube.com/playlist?list=PL-kyUCiIIVS4G99tAKptFA_eoZ5_1UmrV
But you can explore options here:
https://alternativeto.net/browse/all/?tag=tweening
One interesting option is CACANi, which focuses on auto in betweening for drawn animation (but is vector based), it's paid tho. I should try the demo or find a free vers some day xD
https://alternativeto.net/software/cacani/about/
