How do you automate complex employee onboarding?

So I’m kinda stuck developing a smoother process for our employee onboarding and offboarding. We have a process in place for requesting, approving, access, etc however it’s all very manual. Were cloud only M365 with a mix of SSO apps and unique login apps all online. I looked into Flow/Power Automate and there’s some useful bits, but the problem is our enterprise is getting quite complex. We’ve grown up to almost 50 offices this year have several departments and numerous job titles per department. Each office has the same set of approved departments and titles with the same scope of responsibilities. Then there’s the corporate office that needs oversight of a given department across ALL locations. The issue I have automating is we have a matrix of departments, titles, access, equipment and software licenses but the column by row is like 18x40 18 categories of requirements across 40+ roles. For example: a Driver at the D.C. office may need a company phone, Office E1 for teams and outlook access, an ID, badge access to their building, while an engineering coordinator would need a laptop, access to shares, business cards, access to systems owned by other stakeholders who need to approve, etc. Ideally it’d be awesome if I could just feed some AI this matrix of titles & access and say: pump out a user account, with all required email groups, access groups, team chats, and notify all relevant app owners of new hire or fire. I tried to set up a Power Automate flow based off inputs from a form, but I found myself making unsustainable if/ands, conditions, branches etc that was a delicate scaffold of nonsense and maintaining it would be a nightmare. The form was also ridiculous because I needed a header for each location and department to filter titles available and then inputting those as variables in Power Automate was beyond insane. (Imagine 102 variables all saying “Job Title” to cover every option listed in a multiple choice form from multiple sections) I also want to eliminate human error as much as possible. I want our hiring managers to fill out a form. If they choose their location and department the relevant equipment, title, and access options are already filtered. Notices to relevant stakeholder emailed when needed I’ve looked into apps like ManageEngines ADManager plus and it has templates but has lots of weird quirks that makes automated onboarding a bit difficult and empowering HR for official approval means additional user licenses and costs for access. I don’t need a free thing, willing to pay for a product that will do this, but it has to tick all the boxes between IT & HR. So my question is: how do some of you sysadmins in enterprises with >25 locations and >1500 employees deal with this? Hiring manager submits a request form, HR approves and access and resource request list sent to IT for response. Now I know many will be using traditional Active Directory, on prem, and have hooks into a HR system like ADP or Oracle for automation. So I’m specifically interested in any advice from those who’ve worked in cloud only or cloud-heavy infrastructures.