I’ve been doing the above as a consultant for a couple of decades. Here’s what I see:
o As others have said it’s a lot. That said it sounds like management trusts uou. More than hiring someone off the street to take the reigns. This means there is room to breathe and room to fail a little bit.
o Talk to all biz units to learn what services they rely on. Thus will not be 1:1 with servers and applications as you see them. But it’s an important starting point.
o Inventory all the systems that you can see/find.
o identify backups, DR and put together a list of your concerns. Document this and share with management. This will give you cover.
o develop your own priority list. Be prepared for management to give you a different set of priorities. You will need to learn skills of push back and compromise.
o learn to reach “good enough” in the short term. If you try to fix everything elegantly and perfectly other problems will wait longer.