A customer offers (half day) time slots to customers, in order to all together focus on tasks during an online call (typically zoom). Every +- 60 min there is break. It’s very nice and gives a nice feeling of not being alone, it gives a drive, motivation, …
More or less same as with FocusMate.
Some people take a yearly subscription but he wanted to offer also those individual blocks.
He asked me what’s an easy/automated way so people immediately after they paid, got an email with the correct calendar link (ics file) containing the video link (zoom link). Preferably in the Woocommerce system he’s already using on his website.

Here is one way of doing it:
First, define each (half day) time slot as Downloadable /Virtual (simple) product.
Downloadable: so Woocommerce can deliver the ICS file
Virtual: because there is nothing physical to be delivered
That way Woocommerce will handle the emailing the zoom link stuff after payment was successful (=order complete).

This can be a tedious job if you have like 100 products to be uploaded.
Luckily, we can use import feature of Woocommerce to do this in bulk. Given off course you have all the information (e.g. ics calendar file with the zoom link in it) upfront.

To make it user friendly for the buyer, I would put every individual product in a specific category (e.g. the name of the month it belongs to), so you can nicely present it to visitors.

Probably also make sure the products expire after that specific date is gone.