Looking to Standardize Firewalls Globally: Where Do I Start?

Our company operates globally, but each region has its own firewall systems in place, making things a bit chaotic. The UK uses Fortinet, the US is on Meraki, and other regions have Palo Alto and Check Point firewalls. We're considering standardizing everything to one vendor with unified config templates, global patching schedules, and shared policies. This sounds great, but I'm totally new to this kind of project and I'm not sure where to begin. Should we focus on security baselines first, centralized management, compliance issues, or potential latency problems? Since we don't have a global networking team and the regions are quite independent, I'd love any pointers you can give. I'm also curious about potential pitfalls, the tools or vendors that can simplify this process, and whether this type of endeavor usually takes years and ends in compromises. Any advice would be appreciated, even if it's just a warning to consider before diving in!