ICS Calendar Pro supports the Block Editor (a.k.a. Gutenberg) with an ICS Calendar block.
When inserting a new block, simply type /ics
to select the ICS Calendar block.
ICS Calendar blocks function identically to the Calendar Builder, except that the calendar you create with the block exists only in the page where you create it, rather than being listed under ICS Calendar → All Calendars.
When using the ICS Calendar block, you do not need to enter a shortcode in your page.