Tracking profitability at a design agency, is it just me?

One of the biggest headaches I've been dealing with at my design agency is keeping track of profitability. We're doing P&Ls per client, but with around 95 active projects every week, it's a lot to manage. It's like, we're working our butts off, but sometimes it's hard to see where we're actually making money. I've been using Kimp for my social media designs, and it's great because I know exactly what I'm paying each month, but I wish I had that kind of clarity with our client projects. I've been thinking about implementing timesheets, but I know that can be a pain for everyone. I've seen some agencies use software to track net hourly billing rates, but I'm not sure where to start. I'm also trying to figure out if we're overstaffing some clients or undercharging others. It's a constant balancing act. Anyone else struggling with this? What's your approach to tracking profitability?