How to track profitability by project, managing 15 rental units for multiple owners

I started with my own 4 rental units, simple tracking in excel worked fine, then 2 investors asked me to manage their properties and suddenly I'm at 15 units total, everything flows through one business account, rent from all properties mixed together, maintenance costs hitting randomly, property taxes and insurance for different owners all jumbled, complete mess.

The investors want monthly reports showing their specific numbers, takes me 7-8 hours every month to sort through statements and figure out which transactions belong to which owner, that's time I should spend finding deals not playing accountant.

Also maintenance emergencies at night are annoying, plumber needs paid immediately so I use my personal card then reimburse myself later which gets messy in the books, finally set up separate accounts for each property owner so their money stays isolated, makes reports automatic basically.

Also got company cards for my maintenance guy tied to the right accounts with limits so he handles stuff without calling me at midnight, the only solution I found so far was using relayfi with the account splitting thingy they have

If you manage properties for other people how do you deal with the sh*t show that is reporting and knowing which penny belongs where?