I try to keep things as simple as possible, while also attempting to be somewhat organized. All of my income (job and side hustle included) goes into one checking account. Then I set up auto transfers once every 2 weeks on Friday into my other account (same bank for insta transfer) for what I basically want to pay myself. That's my personal daily use checking account. Everything left over in that other account either is auto transferred once per week (predetermined amount for automation) into my Emergency Savings (same bank again for reason mentioned), auto transferred to my Ally online savings (only for their bucket system which i use for sinking funds), and the remaining amount that doesn't get transferred is my next real estate investment plus the CapEx/Vacancy.
Example (fake numbers): I get $8000 income over the course of a month, all of which deposits into check acc 1. I know that I spend $3600 on expenses every month so I have auto transfers set up every other Friday to send $1800 to checking acc 2, which is where all of my daily transactions come from. I also auto transfer every Friday $30 to my Emergency Savings acc, and $150 to online savings (sinking funds). I’m not gonna do the math but let’s say at the end of the month, I have $2500 left over that didn’t get transferred from checking account 1. That amount will be saved every month (assuming my income doesn’t fluctuate too much, which unless you are in sales, a real estate agent, etc, shouldn’t matter too much)
Sorry I know this is kinda long and kinda went a little more into personal finances, but that’s what I do. Everything is automated for the most part and I can always adjust how much I want to pay myself
Edit - I didn’t mention it, but I just track income vs expenses on google sheets that I also use for taxes. I don’t have a lot of transactions going on so it takes me maybe an hour per month to update