I hate sharepoint (online)

I've been in IT for over 15 years, but new to sharepoint. I hate it with the darkest passion. Here's an example why. User calls and wants a way to let 3 people edit an excel file at once. They also want to share it with mobile users as read only. (Its a schedule of sorts). No problem, this sounds like a problem for sharepoint! So, you create a new sharepoint site. You set yourself as the the owner, because your the IT admin, that's why. Now you go to your sharepoint sites list. Its not there, under recent or favorites. Why, b/c its new! But your the owner. Tough. So you go back to admin and find the the URL. Now you want to set security permissions. Oh look, Microsoft created groups already, in O365. But I want to use my existing AD groups. Tough, we created groups and REALLY want you to use those. But you finally find the link to Advanced security. You add your two AD groups, one with edit, one with read only. You save the changes. You refresh the page. But the groups are not there! Why? Who knows. So you add them again, now one shows up. So you do it a third time. Now the Read only groups is listed as a visitors. Their not visitors, their AD users with read only permissions, BUT THAT'S WHAT THEIR CALLED. So you think you've got the permissions fixed. So you fire up Excel and go to Open->Sharepoint sites. But ITS NOT THERE. Why? Who knows. So you go to "Add a place" and SHAREPOINT ISN'T There. Why? Because its already there, just without what you need. So you pound the table in anger and decide to explain to the user how to navigate to the SharePoint URL and open it from there. BUT it wants to open in the web version of excel. What is this? The user is confused. They want to be able to open it from Windows Explorer, just like the Shared drive. So you walk them through adding it and signing into one drive. And then the users decide this all too confusing and just go back to emailing each other multiple copies and loosing track of which is the latest. (BONUS: When you were in Sharepoint you discovered about 87 other sharepoint sites you never created. How did they get here? Teams Creates them! Oh, and sharepoint DEFAULTS to allowing sharing files with ANYONE and with FULL WRITE ACCESS.) I simply cannot believe that anyone, especially in larger corporations accepts this dumpster fire of no security where the answer to every problem is "Wait 15 minutes to 48 hours and it might work."