What's the best way to display company calendars in SPO?

[Anthony-123]

We want some calendars on SharePoint to display Holidays and Employee PTO (among other things). I keep hitting a wall with old Sharepoint instructions. (This should be stupid easy!)   

Do I need to create a Public Group / Mailbox in Exchange? (This seems outdated)  

Do I create an App > Calendar? (This looks horrible) 

Do I need to create a dedicated Group just for calendars? (This seems excessive)   

I've created "events" calendars on my team sites but these appear as 5 item lists. I want a fully operational calendar that anyone on the tenant can subscribe to.  

Do you have to create a calendar in Outlook first then post it on SPO or can it be the reverse?  

It's really frustrating that the only information I've found is from 2015-2017. By the time I find out the instructions no longer work or are outdated, I've spent 30-60 minutes on the proposed solution.   

For 2021, how should I create these new calendars and display them on our SharePoint site?  

Update: So, I've tried using the Event web part as described in a Laura Rogers Power Hour video from December 2020. She found a hack to change the classic calendar to modern. This is promising but when I edit the event to set it as reoccurring, it no longer appears in the Event web part.  

[#2]

Looking to your message i understand two things... but both are just as assumption;

if you are looking to just show the Company calendar with two specific categories i would suggest going the route of creating a SharePoint Calendar App (kind of Classic Calendar) setup Views and overlay so you have two different color codes and you can even setup uniqueness and can play with permission from the setting section for that specific Calendar list.

you can Also try to use the new Microsoft List in Teams, create a new lists and name it while in the view section try to select the calendar view (it is not the channel calendar app) this is a Sharepoint list which has Calendar view now but will not be able to color code like overlays.

the third option you have could try Microsoft Booking i know it is only for meeting booking but seems from your message you need end users to book as well...

though with above 2 options you could use the same but booking is totally a different beast to give a try....

[#3]

Just focusing on holidays, for the moment... I've continued to mess around with the calendar app and lists. I might be able to make this work but I've hit a wall with setting an event as reoccurring.
When viewed as a list, I don't see a function to set an item as reoccurring. When I use the Event web part on the SPO site, reoccurring events don't appear. Also, the 'create new event' form doesn't offer reoccurrence.
So, if I were to just go through and manually enter all the holidays, etc. I'd be in good shape. I do not want to do that.